Firstly, this reflects merely your frame of reference, No wonder vulnerable white girls were groomed by Asian male gangs when there is such a lack of respect towards white people from the Asian community.
You are totally discounting the rape and sexual abuse of non-white victims and survivors and non-Asian perpetrators. For some reason you focus on the minority of cases with a racial element.
Secondly, Why on earth would you introduce yourself as part of the LGBT community when your teacher only asked your name and something interesting about yourself - the teacher meant your hobbies, your interests - not some completely unnecessary disclosure about your sexual orientation and sexual preferences - just attention seeking and then later complain of bullying. Sexuality is something to talk about privately among friends or at least people you have got to know - not to a class full of strangers.
A lot of people learn from experience to quickly explain certain characteristics about themselves. They quickly explain that they are straight (despite being camp) or blind (despite wearing sunglasses) or that they have MS (despite appearing perfectly well this morning) etc etc. They have learned to just get it out there early doors.
Why tell new classmates on first day you are bisexual - it is not normal conversation to discuss your sexual preferences with strangers - it is nobody elses business but your own and if you decide to make it the sole topic of your conversation then expect endless questions and curiosities rather than people getting to know you as a person.
I disagree, I think that sexuality is a highly political and public issue. I note that you didn't have a problem with the (white, straight) person talking about her ex's vasectomy.