HoneyVision said:
Cannibalism is a barbaric practice that usually involves the death and murder of someone to achieve it. That is pretty undefendable if you ask me. Necrophilia is often done without consent, which also makes it illegal and wrong by definition. If the deceased gave written permission for the deed before they died, then a case could be argued there, but as it is, it cannot be defended. Suicide I believe shouldn't be illegal. Help should be given to contemplators, and every effort should be done to try and sway their decision, to convince them that it is not worth it. But if they themselves do not wish to live on this earth, then that should be their choice and theirs alone. I guess suicide is much more grayer than the first two in this regard. Bestiality, as I said, is a topic I haven't yet come to a solid opinion of. It's something I still need to think about and form a conclusive stance on, so I can't really say right now about that. Scat and piss fetishes are not problematic in the least. As long as they're consented and done between legal adults, I see absolutely no problem with it.
As for the question, of course a line must be drawn. Whenever consent isn't given, and it's forced. If it borders on harming people and mistreatment. Things like that. I do not believe we have the right to oppress other people's sexual lives just because we find it "icky" or gross. Many people find feet to be a disgusting part of the body, should foot fetishism be looked down upon or made criminal? No, no way in hell. That extends to the previous ones you mentioned, scat and piss (I forgot the proper terms). If two or more people are of legal age and they consent to it, then they aren't harming anyone else in their sexual indulgences and I see no rational reason to oppress them for it.