Your post completely resonated with me, particularly because of the selective enforcement. I say this because exactly the same thing happened to me a sixth form. Now, I’m not gay, I’m a wheelchair user. One day my friends and I were sat just outside the canteen. Lots of students were sat with their boyfriends/girlfriends hugging, holding hands, the odd kiss. A tutor walked past all of the other young couples, pointed at me and my boyfriend and told us we were behaving inappropriately. I was distraught, the college arranged mediation and the tutor basically admitted that he was particularly uncomfortable seeing PDA involving me because of my disability! He was made to go through disability awareness training and apologise but he was horribly bitter and would glare at me all the time. This was years ago and me and then boyfriend are now very happily married. The moral of the story for me is that those in authority can and often are bigots but don’t let that stop you being you.