There is someone I know who is really into kink/bdsm/fetish. He is one of the several organizers at social dances I attend. Note, these dances have nothing to do with kink/bdsm/fetish or anything sex related. This person often acts in lewd ways that makes me feel uncomfortable. For example loudly talking openly about kink and alternative sex. Last time he loudly spanked a lady's bum in front of everyone when she was bending over and then said "it's alright, it was totally consensual".
I'm in my late 20s and this guy appears to be in mid 30s. Technically this dance is for all ages but most people there are in the 20-40 range. It's in a very liberal metropolitan city. I try not to talk to this guy but he's loud enough that I inevitably overhear him.
To me, this kind of behavior just leads to an uncomfortable social atmosphere. I don't think it's fair that he is so open about it in public, but it would be rude if others talked about their sex life.
How can I get him to to cut back on doing this behavior so openly, without sounding prejudice?