I didn’t even know my teachers first names when I was coming up; let alone their sexual preferences. This is personal private information. Their personal business not mine.
Only thing close knowing their personal business, in the case of female teachers, was if they were married, since you would use Miss for unmarried and Mrs. for married. That was my only concern, do I use Miss or Mrs. don’t care who you’re married to.
The teacher in the OP made it all about themselves; very selfish of her.
Her only job is to effectively teach the curriculum and make sure the students are learning the information to be well equipped for the next grade level or graduation, whichever comes next.