Why do people assume I'm gay because I support gay rights?

Same thing happens to me

Maybe they think your hiding in that closet?

Just a suggestion...if and when you say you support the rights of Gay people, you might start the comment with "Even though I'm straight"....that should make them understand that you are an open minded person

there are still a few ignoramuses out there unfortunately.

People are total idiots.

That..idek. I guess they're a bit egocentric. Like if they don't do it, they assume everyone doesn't unless they're gay.

because people are dumb.