Because not everybody is as accepting of our inherent differences as you.
Gay... really is not an aesthetic value. I have a friend whom I had known for several years before learning he was homosexual. Nobody would have guessed it, he was the straightest seeming guy around. Gay is not what you see on tv, nor a stereotype, THE stereotype formed by society.
There are too many points in your argument to pick out individually, a lot of it's pretty hypocritical and makes you sound like an utter bigot.
If someone you know approaches you and states that they're a homosexual, you can just as easily choose to ignore that. By kicking up a fuss you're facilitating their alleged behaviour, creating a song and dance (or is that a bit 'gay'?) about it makes you just as 'guilty' as them.
'I don't like it when gays are all up in my face about their sexuality'
I don't like it when people criticize others who are simply trying to avoid social faux pas and misunderstandings and make an attempt to engage with their fellow people.
Maybe you're sick of how your fellow workers go on about poofters, faggots or queers, or how that girl in accounting has a sweet ass. It's a fact of life that these things are said in the workplace, and if you're offended by them, your boss has the right to know why, and you have the responsibility to tell him.
Inb4shitstorm.