Why can't I compare the treatment of gays to that of other persecuted minorities?

Honestly in root they are all persecutions so they all have something in common. They were all persecuted because of what they believed in, what they followed, so why can't I compare the treatment of s to that of other persecuted minorities? Seriously when a persecution starts it is always appropriate to describe it with other minorities that have been persecuted to show just how little this society knows. Honestly even history teachers, I had a history teacher like this, that would persecute against people. Seriously they claim that they know the past yet the teacher doesn't like people who challenges her reasoning skills so the teacher ignores the students. We haven't learned much of anything, have we? Even those who claim to know history are just as ignorant to what is going on in the present time situation.