score:1
Right. I have two flatmates at present - a Mexican guy and a German girl. Both have been to these places, so I asked for their knowledge of the area.
Mexican - it's totally fine. It's like tourists to Sydney being told 'watch out for sharks in the water' - yes, crime exists, but it's not likely to happen to anyone passing through. It's more likely to happen to people who live there - he knew a lawyer who had 'dealings' there, and he disappeared. But they're not going to direct attacks towards tourists. He also showed me a Facebook from a friend who is currently there - it looks beautiful and now I want to go too :/
German - went there, it was fine, felt very safe.
Conclusion: If you're not a part of the community, you're probably going to be ok. Of course, bad luck can happen.
Also, Mexican suggests looking at Lake Camecouro nearby. Pictures online look amazing.