The problem here is most gays who are fired, harassed, found out to be gay, are the ones that are "out of norm' in some way.
If somebody's mostly like everybody else except for their sexuality, how will I know unless they tell me. I barely know if coworkers have boyfriends, girlfriends, or even are maried, unless they tell me. Their family or spouse almost never comes to work.
So, its if you look gay, which often relates to gender expression that you are most at risk. So, what on earth are they protecting with this ENDA! They're protecting themselves from creep employers who pry in the lives of all their employees; maybe there should be privacy laws to protect all employees from such employers...