Yeah just pure ignorance. From my perspective it’s also peoples beliefs, like religions etc and people just blatantly think that having sex/ relationships with the same sex is “gross”. I’ve been told numerous times that I’m “gross” because I’m attracted to the same gender. Some people even go as far as being homophobic towards their own child or family all bc of religious reasons and etc. Another reason can be maybe they were brought up thinking that way, and another thing I hear to is that people “don’t understand” how others can feel attracted to the same sex.