So I called my recruiter up to talk about the concerns I've been having, specifically the exposure to "ugly stuff".
He told me he had placed about ten people doing the same thing I'll be doing, and they haven't reported any complaints at all. Most of them are still working, a couple got promoted in under two years, and he says they've all been very happy with their jobs.
I was very transparent with my doubts, and he assured me that he would never have me working a job where I'd have to be exposed to heinous shit on a daily basis. It's still a possibility, of course, but such things would be a rarity, as I expected. He said at worst I'd be seeing idiots shooting themselves up, which I don't have a problem with. Fuck up your body all you want, just don't drag children into it.
So that put my mind at considerable ease. I feel a lot better, but am still going to have my guard up during this training period.