Long windedness ahead
Suicide Bomber
Okay so the Suicide Bomber one I've seen done a few times and they usually fall into the that school shooter/rooftop sniper theme. You're basically playing as some nut trying to kill a bunch of people. My only problem with these is they're usually not done very well. It's not like anyone goes into the mindset of being a suicide bomber and as a few people pointed out they tend to be pretty short because the writer doesn't consider anything more than the actual bombing itself.
I mean the idea of the whole planning and plotting of your righteous journey before meeting 72 virgins might be interesting, just haven't seen it done yet.
Going the humor/satire route is certain valid, but I haven't really seen this done yet either. (Seen more humorous attempts at school shootings, guess its funnier to kill a bunch of people at school you don't like)
AIDS Crack Whore
The AIDS Crack Whore I've seen quite a few variations of. The best one that someone actually put thought into was "You Are a Prison Bitch."
The rest of these types of stories that I've skimmed though never really evolve past the writer typing a few misspelled words of how you're sucking dick (real and glass) and then you dying. (Usually with a Lol at the end) These tend to be very short as well.
I do think some of you are right in that something much deeper could be written though it would probably still be depressing as all hell, but hey some stories don't have happy endings.
Again making it humorous is certainly possible, in fact that's probably why the best one I read of this sort of theme was the Prison Bitch one.
Nazi Death Camp Guard
Interestingly I've never actually seen the Nazi one remotely attempted. I guess their aren't many white supremacists into writing CYOAs. Making a story about playing as being part of the organization that performed the Holocaust aside, it still has the potential to be interesting. Probably would need some detailed knowledge of WW2 history and such to do it justice.
I imagine the easiest way to approach it would be trying to make the protagonist sympathetic by having him trying to help out the prisoners when he could and him having a lot of difficulties at doing his job.
I don't think you could do this theme humorously though. Well, you could but it would basically amount to "Dead Jews Lol." and then getting several angry comments written to you calling you a Nazi bastard and a surprise invitation to the Stormfront forums and you probably don't want that.
Pedophile
Finally, I have seen a couple attempts at the pedo protagonist. One of which even got taken down on Infinite when a few people complained about it. The dude snuck a similar less graphic story on there much later, but no more fuss was made probably because it was forgotten about and not even popping up on the main reading list anymore (It was less than 20 pages) While it wasn't extremely graphic, it did kind of invoke a sense of "ick" especially since you were playing as an enthusiastic little girl (It was like a sex cult or something) which actually might've been worse than playing as a pedo. Made it extra creepy that he added random pics of little girls to his story.
Another one wasn't graphic at all, it was actually about a pedo and his mission to lure steal a child away from the playground or whatever. Focused purely on the hunt and usually ended with either driving away with the kid or getting caught. Quite frankly it was rather dull and seemed more like a "Got a kid in my trunk Lol." type thing. Wasn't particularly interesting.
As odd as it may seem, I have yet to see a humorous attempt at this sort of CYOA. You would think that someone making a theme around it might attempt to soften the ick factor by doing such a thing, maybe by doing it South Park/Family Guy style, but haven't seen it done.
But even with humor (which may or may not be funny to some people) I don't think you can really "champion" the theme of a pedo protagonist. Even if you say took them into a different setting to make the premise more acceptable you can't really do it like you could easily do with the others
Put the following in a fantasy or scifi setting…
Suicide Bomber- Any suicidal fanatic with a cause can be used. Doesn't matter what they follow, the religion might be an expy of a real world one or not, but it doesn't matter. It'll get more of a pass.
AIDS Crack Whore- The protagonist is a succubus (or incubus) Basically you're playing as a demon who is obviously going to indulge in reckless behavior some of which may include taking drugs on a regular basis for fun. They're also having A LOT of sex and killing everyone through it. If you want a Scifi example, Morinth from Mass Effect was basically whoring around killing people with SPACE AIDS though she probably was more addicted to killing people than any drugs she may have taken.
Nazi Death Camp Guard- This one is really easy. Take any race, human, alien or a fantasy based one. Make them extremely militaristic and xenophobic. Create your protagonist as a member of said race running a concentration camp with their hated enemies as the hapless prisoners. (Which is probably everyone) Controversy averted. In fact now you can make an enthusiastic death camp guard with no problems.
Pedophile- Yeah, see it just doesn't work. A pedo is still going to be a pedo no matter what setting they're in. Someone molesting pre-pubescent children (regardless of race) is just going to be scum no matter what. And no, some guy going around molesting halflings because they're small and childlike doesn't count. He's just got a halfling fetish. A terrible terrible halfling fetish.
Like I said, I don't doubt the possibility that an interesting well written CYOA is possible with such a protagonist, its just I'm not going to be the one to attempt it. Not a topic that would interest me for one thing. I'd actually find attempting to make the floorboard story interesting more desirable.
Next story theme: Floorboard in a Nazi Death Camp