Patreon drew a line in the sand on bestiality, rape, depictions of minors, necrophilia, and incest; all of which are not allowed in games. They require all public content to be appropriate for all ages (like Lust & Passions avatar). They've made it pretty clear, and some games get around the rules by releasing patches for their games.
These rules were last updated in October, a week before the dev released this game. Anyone who tries to work around these rules does so at his/her own risk. Patreon has it's issues, but devs need to read the community guidelines