I'll leave to racial stuff out of my reply since this is suppose to be talking about 'gay rights' or whatever...
Have I experienced discrimination because I'm straight? Yes... Back in my university days, one of my part time jobs was working in a high street retail high fashion menswear store. The section I worked in had 5 people, apart from me, the rest of the crew were gay. I had a great time working with them - they were professional salesmen and knew their stuff and they were generally good guys to work with. Some were genuinely very nice people. However, once outside the store, I'd trouble socializing with them.
For example, after a long and busy Saturday, the usual comradary thing to do was to go out for an after-work drink. When it came to choice of venue, it would always be one of the gay pubs or bars that were off the side of Oxford Street. Did I have a choice? No - the majority would decide. If I preferred not to hang out in a gay bar, I would miss the chance of socialized with them and being part of the 'team'.
So, I went with them to a gay pub/bar... That's effectively part of the 'scene'. For gay people I'm clearly not gay. I had been talked to by people in those establishments querying who was I with... If my answer was 'I'm waiting for friends', I would have been invited to wait outside until my friends arrive. Once the only Chinese person in there probably didn't help, as I stuck out like a soar thumb.
In effect, being a straight guy with a gay friend in a gay bar is ok... But a straight guy by himself in a gay bar is a big no-no! What is that?? If a gay person being asked to leave a normal pub/bar because he's gay and he's not with a straight person, it will be an outrage. But it is not so the other way round... What kind of a world is this?