My mom was big on setting boundaries. What i could watch, who i could hang out with, the language i could use, etc. Its important to remember that these boundaries will only be enforced when a parent is around; you can't realistically shelter a kid from ideas you don't like. As i identified more and more with the things that were banned from my house, the very simple solution was stay away from the house. I did not feel free or comfortable to be myself at home, so why would i want to stay there? My interactions with my parents became very short because i always felt as if i was hiding something. By the time i got to move out, my mother and i were literally not talking to each other. That went on for about a year before i was willing to try connecting again. These days, my mom has learned to accept that she may not approve of everything i do, everything i like, the way i talk, but she respects that I'm my own person, and we're much closer because of it. It feels really great to finally be able to just sit and have a real conversation with my parents, all while being myself.

Obviously there are boundaries to be drawn when being a parent, and no one can tell you what's okay or what isn't. Just consider that in today's world, you're probably not able to monitor all of the content your kid is exposed to. Focus on teaching rather than censoring imo.

This whole story may or may not be relevant to you, but the first line of your post reminded me of my own experiences, and i wonder how different things might have been if i could have watched south park and played mortal kombat at home.

Tldr there's probably worse things than a 15 yr old hearing a sex joke