People who say "it's no big deal" are being selfish. Even if it's not a big deal for them (it probably is) it would be for most parents and friends out there. It would be news to them, most likely. Even if the parents were respectful and chill about it, deep down they know it's a big change, and it is.
Coming out can be a difficult and traumatic experience, especially when a family does not take it well.
It should not be a tremendous issue when a gay person comes out to their family. But it also should not be a moment made light of.
Family members need to understand how difficult it can be for the gay individual, and they should respond in a way which best assuages some of that pressure and fear.
If that means making a big, happy deal out of the announcement, so be it. If it means having a quite, happy family dinner to celebrate the honest discourse, then that is fine as well. Every persona and family is different.
A person's sexuality is arguably one of the most important aspects of their life, and should be regarded as such. That said, the ultimate decision as to whether family and friends should make a big deal about it should be up to the person coming out; If they don't want it made into a big deal then it shouldn't be, but if they see this as a turning point for themselves then it would be rude to just treat it as trivial.
This is kind of a tough question to answer, but I think that if my son or daughter told me "Dad, I'm gay." I'd probably just be like "Oh cool.". However, though I wouldn't care very much, I think the child would probably consider it a big deal, and would be shocked that I didn't care. I guess I just don't know how to react.
If everybody treated you good when they thought you were straight, it should not matter because if they were your real friends, they would forget about it and just keep things going on like normal. I have never come out because I'm scared of what my parents will think, but meh.
When you think about it, if someone told their parents "hey look I'm straight." they wouldn't think anything of it, so why should people think of being gay as such a big deal? It doesn't really make sense. Love is love, it's that simple and who you love definitely shouldn't be such a big deal.
If I told you today that I like cinnamon, it wouldn't be a big deal. Making things a big deal elevates the situation to a matter of some importance. Someones sexuality is not my concern nor is it a matter of importance. I didn't tell my parents I have sex with women, why should a gay brother or sister tell me they have sex with other people either? If you simply refuse to make it a big deal, it generally becomes culturally accepted.
There really is no reason to be excited when 'coming out'. Life, is life, is life. Do you realize how ridiculous it would be to have a sit-down with the family and make an announcement "Family... I'm Straight" and everyone stands up and says "Well good for you".. Please, that is just silly.
The sexualities of your friends and families doesn't change the relationship you have with them, or had with them. They're still your friends and family, thus their sexuality doesn't matter. You mightn't like the idea of 'what they do' as so many seem to be fixated on, then don't think about it as you don't about the sex life of your heterosexual friends and family.