Growing up in a separate culture within your culture also probably makes a difference, too.
But yeah, that's why we make a big deal about announcing who we are. Because the more of us there are, the more power we have to fight for the rights we still don't have. It's less about everyone having to announce it than it is just... wanting to add our own voices to the ongoing fight for equality.
Maybe in your home country, people are still scared to. Which is understandable. No one should do anything that makes them feel unsafe, and there are so many people that have lost friends, family, and jobs over just being who they are. That fear is completely understandable. Hell, my boyfriend has one parent who is accepting of his sexuality and one who isn't. You just. You never know.
Hey, whatever and whoever you are, you've got a lifetime of figuring that out. Just be true to yourself and everything else falls into place eventually.