LGBT students should be treated as other students, and as such, should have the same expectations as other students. They're not entitled to special treatment, but rather, they should be getting the same treatment as other students. Their sexual orientation should have no bearing in how the teacher treats them. They're students first and foremost and should, therefore, be subject to the same rules and regulations as their peers.
More often than not, teachers fall under the demographic where homosexuality might not have been so widely accepted. In such cases, they too should learn to accept and learn of the situation. If a teacher makes untoward remarks out of pure ignorance, then discourse should occur so they can take the opportunity to correct themselves. However, if a teacher acts spitefully and in a manner that is detrimental to the well-being of a student, then they're not fit to be teachers.
Teaching is a profession where one has to learn continuously. You may have your biases, but you're there to impart knowledge to the next generation, not your hate and prejudice.