Well, saying "I don't care" is probably the most basic form of tolerance.
That's basically my opinion on quite a lot of things including homosexuality. I simply do not give a shit about the sexual orientation of 99.9% of the human population. Nope, don't care.
Whenever I've met and talked to homosexual people, I actually told them exactly that when they said something like "Oh, and btw... I am gay/lesbian." Most times I replied "...and why exactly did you tell me? I don't give a damn."
Funny fact: a lot of them reacted rather agitated. Which again I don't understand. Am I supposed to care about who the guy I met 20 minutes ago for the first time is fucking in his spare time? Am I supposed to be like "Uhh... you're so cool now cuz you're different and all that."?
Sometimes it's weird and I don't know why. I do not care and you're hardly going to make me care.
Hopefully, in the future, everyone will have as enlightened an outlook as you have. I think the reason people make such a big deal of "coming out" and announcing their sexuality to others is that, unfortunately, society hasn't always been as enlightened as you are and many gay people have been repressing themselves since a young age.
So long that it requires a strong affirmative step for them to come to terms w/ their identity. My theory is that that's why a lot of people act like really flamboyantly gay for the first few years after they come out and want to announce it to everyone and march in pride parades and stuff. 1. To establish their own identify for themselves. 2. To support others who haven't come out and 3. To combat the hateful and intolerant views that predominate in many economically developing regions like Russia, Sub-Saharan Africa and rural Southeastern U.S.
So, regarding the random people who feel the need to tell you this essentially private information, it's the fact that, what should be something completely private, has been made public by people who aren't as cool as you. So, I agree w/ HeskeyTime, this shouldn't be something that people should feel the need to have to announce to the world, but, sadly, for the time being, that's just the nature of the battle being fought for acceptance.