People are still being fired for being lgbt. It's rare but it happens, and smart companies will mask it under other disaplinary actions. People still get beaten up/harassed for it too. When was the last time either action happened because the victim was straight? We've come a long way since people were arrested for being attracted to the same sex but we still aren't 100% there yet either. Our current government was exploring the idea of repealing gay marriage until they realized it would be political suicide for them.
About being fired:
Their workplace doesn't need to know they're gay. If they tell their coworkers, or boss/etc, then it's on them. Sexuality, like many other things should only be expressed in the appropriate places. You wouldn't go to a motorcycle meet in bondage gear, you'd go to a bondage party in it. As the same, you wouldn't go to work shouting I'M GAY while wearing all rainbow clothes and apparel. It's just not the right place (ESPECIALLY a professional place.) You don't need to announce it everywhere and shove it down people's throats (sorta like religion... which reminds me of a funny quote)
"Religion is like a penis.
It's fine to have one.
It's fine to be proud of it.
But please don't whip it out in public and start waving it around,
And PLEASE don't try to shove it down my children's throats."
Furthermore, if someone wants to be special and show their specialness around everyone else, they should expect to be treated differently; and suffer the consequences of their actions. That's just how the world works.
As for the comments someothers made about straight pride being every other day where you can show PDA without being harassed. I do that with my current boyfriend (well, I keep the groping out of sight. but hugging, kissing, holding hands, etc.) Let's face it, 99% of society is too chickenshit to say anything; the 1% who do will back down when you stand up or ignore them; at least here in Canada. Sure we get a few weird looks here and there, but nothing ever comes of it.
Sexuality is not a choice, but who you sleep with is. You don't have to be attracted to someone to sex them up (especially if you're drunk... I'm sure most guys here have had a girl or 2 they're not exactly proud of sleeping with.) Someone could choose to have sex with the opposite sex to make it appear as if they're heterosexual (because unless you tell someone, they don't know what you're attracted to.) Heck, if they do it enough they might just turn straight or bi.