score:5
As you say it was no doubt a bit of both, and often in the same person.
Many were tired of war after the losses of WW1, and were still struggling under the economic problems that dominated the 1930s (ironically it was pretty much WW2 which ended those). At the same time support for eugenics and anti-semitism were strong in the USA just as they were across Europe.
The first led to an overall isolationist view among the people, the second especially to people having sympathy for the German laws regarding Jews and other 'undesirables' (in fact similar laws were in place in the US regarding mentally handicapped people, blacks, etc. and to a degree remained in place for decades after the war, think the programs promoting prison inmates from getting themselves sterilised (I think in return for reduced sentences), forced sterilisation of mentally handicapped people, etc.). It wasn't until the true horrors of large scale executions of such people by German forces came to light that sentiments in the US shifted towards open animosity for Germany, their conquests were far from peoples' beds and especially with the memories of WW1 fresh in their minds they didn't want to repeat that.