As a rule of thumb, if you get reported over incest/loli content on Patreon, you're out almost instantly once they've checked. There's a recent thread in the dev forum of someone who just had their page terminated because the MC and his "landlady/caretaker" looked extremely similar and had some kind of mother-son relationship, although it was never stated they were family. Still, that was enough for Patreon to take down the page.
The one rule they seem to not apply very strictly is the one about "sexual violence". Last time I checked, simply "lying to get sex" is considered as sexual violence, and thus could get you banned, which means around 95% of the games in there should be done on Patreon. Still, unless there's no outright mention of rape on your page, you'll be safe. Heck, Corruption of Champions I&II and Trials in Tainted Space all rely on the very philosophical concept of "to rape or to get raped? That is the question", and Fenoxo and Savin are still going strong on there.
For Steam, all goes except underage or underage-looking, to such an extent that I'm not even sure I'll be able to get my game on there, simply because the MC was a kid in the prologue and there was sex happening nearby, although he's not even seen it, let alone participate in it in any shape or form.