What is the source of hatred often perceived by Christians in western society?

The Bible is clear that Christians will go through persecution (from a spiritual origin) due to Christ's name alone. However, we live in a time that all customs and beliefs are under attack from all angles. There's clear anti-Christian elements in the world today, but no more than the hate for Jews, Muslims, etc that is also very evident. I believe that all of the above answers/comments have a ring of truth to them - some illustrate the spiritual source, some illustrate the feelings caused by abuse from Christian hands, while others illustrate the true bigotry that Christians must live with as anybody else.

In short, I believe basic human nature is a major cause, though institutionalized elements are at work as well. Can we say this is all in Christ's name? No - it's effecting everybody in our age. Will it get worse for Christians because of Christ's name alone? Only time will tell, but I believe that the Scriptures are clear on it.

While working in a penitentiary chapel I saw all levels of religious conflicts, some which lead to death of both inmates and guards. I have witnessed these events and have spoken with perpetrators of these acts after the fact. Its surprising how common the feeling of injustice was amongst these groups, yet each harbored the same basic prejudices. It was truly maddening, and very sad.

For the most part it comes down to plain old discrimination. Many people hate what they don't understand. Non-Christians don't have the market cornered on it either. As Christians it is important we respond with love an understanding.

Check out MLK's stance against the Vietnam War and I think you'll learn a great deal about it.

MLK went so far as to give speeches that Militarism, Materialism, Racism, and Poverty were all bad things, and lived his life to his death pushing these sorts of ideas.

Although this sort of life is a good Christian one, it really doesn't sit well especially with those in power that wield most of the Militarism, Materialism, and that cause most of the Poverty.

People don't really hate Christians any more than they hate any other group. In much of the world, Christians have a place of privilege, embedded in society to such an extent that it's assumed that everyone you meet is a Christian, and Christian holidays and norms are part of the social calendar. (Witness the absurd nonsense spouted every year about the "war on Christmas".)

In other parts of the world, Christians are a minority, but I've seen no evidence that they're discriminated against any more than any other minority.

The "hatred" you're talking about is actually two (distinct, but related) things:

• In places where Christianity has long held sway over society, where non-Christians were distrusted, and Christian beliefs were enshrined in legislation forcing everyone else to follow them, Christians are now losing that power.There are fewer prayers in schools, Christian "morality" is not forced on the world at large. Non-discrimination acts are put in place. Christianity is moving from a place of privilege to a position of equality. That means it's losing power, but it's not actually being discriminated against, and it's far from being hated.
• The Bible says that Christians will be hated (see @Mason Wheeler's answer). That means that Christians have an investment in being persecuted. They want to be persecuted, so they'll take any small slight (or even loss of privilege) and interpret it as hatred. It's a persecution complex, and it's not healthy. This is most common among right wing authoritarian Christians, who feel that they have the right to run everyone else's life. (There is in fact good documented evidence that one of the most socially powerful groups in the modern USA, white evangelical Christians, have a serious persecution complex.)

The most obvious example of both the above points in action together is the people who claim that use of the phrase "Happy Holidays" discriminates against Christians. What? So not assuming that everyone is a Christian is discriminating against Christians? Huh?

In addition to the reasons posted in other answers here. (misunderstanding, threats to social systems, almost legitimate social stigma), we should add that the basic reason the gospel is not welcomed as good news throughout the world is our attachment to sin.

And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil. (John 3:19 KJV)

Misunderstandings are what happen when people haven't seen the light come into the world because it has been presented to them as darkness. The recent castigation of the priesthood is more and less legitimate, more because there is real darkness present in the allegations, but less legitimate because this darkness people use to excuse their own darkness. Instead of throwing light onto clergy and self alike, it is often more comfortable to point fingers, as though God were fooled by our misdirection. We fool ourselves.

A threat to a social system is even less legitimate, for the situation is that light has made people uncomfortable, and we instinctively squint our eyes when light is so bright as to be painful. But finally, at the root we all do things we know we ought not, and leave undone what was God's behest. Willingly we turn from the light and wish it would leave well enough alone while we perish in darkness. That in us which is of the world, the flesh, the carnal man within detests Christians because Christians are salt and light. Light reveals, and salt magnifies the true flavor.

I don't think non-Christians even bother to separate the various Christian sects from each other, let alone crazy people from "real" Christians. Westboro Baptist Church, multiple Republican candidates who all say God told them to run for the presidency, and those countless pedophiles who are also priests or ministers: what's not to hate?

Christianity knowingly and publicly commits hateful atrocities on a daily basis as part of sanctioned doctrine. While we all know that evil done in the name of religion isn't religion's fault, Christianity's been screwing up since well before the Crusades. Christianity is practically rabid about its missionarying; outsiders probably think it should start missionarying to itself.

It's a sin to be gay? Fine, it's also a sin to eat shellfish. Non-Christians can read the bible as well as anyone and they know that hatred is deliberately encouraged by many Christians.

See John 15: 18-19 (KJV).

18 If the world hate you, ye know that it hated me before it hated you.

19 If ye were of the world, the world would love his own: but because ye are not of the world, but I have chosen you out of the world, therefore the world hateth you.

Why do people hate Christians? That's a pretty broad question.

In some cultures, for example rural Hinduism, Christianity's message of favor for the poor is a real threat to the traditional caste system. I know the caste system's outlawed in India, but it is still ingrained. So Christianity catches some flak there.

In other cultures, like urban Alexandria in Egypt, Christians and Muslims fight each other and attack each others' houses of worship from tribal fear. Each group believes (usually falsely) that the other group is getting unfair preferential treatment. There are also long-lived dehumanizing myths in each group about the other. (No, they DON'T eat babies for breakfast. Seriously.)

In American culture, there's an unfortunate history of coercion and abuse by various churches and their clergy. People sometimes yell rude things at me when I'm visible in clergy clothing in public, especially in the company of my children or children of my parishioners. I am quite sure that's because of the recent child-abuse scandals. Do I wish people would stop doing this? I'm not sure. If that rude behavior prevents the abuse of even one child, it's worthwhile. Meantime, I have two cheeks.

It's important to avoid self-righteousness when reading "blessed are you when people revile you on account of the Son of Man." (Luke 6:22) It's NOT good to be hated and reviled. It's not good when others dehumanize you, or when you dehumanize them. It is good to stick to your principles without caving to pressure.