I don't need to go back in time. I regularly speak to my 91-year-old grandmother, who is absolutely fine with all of that.
You have a revisionist view of history. It's not like being gay or rebellious is a new thing, our grandparents were once young and did these things, too.
If you think that homosexuals were accepted as well 70 years ago as they are today then I am not the one with revisionist history. The key word in social media is media. In your grandparents day, that would have been radio and early television. I don't see a lot of openly gay characters on the Dick Van Dyke show or I Love Lucy. As society changed, they began to appear in media. The younger generation grew up with more exposure to it, so it wasn't as big of a deal. The new youth is going to grow up with differing views of privacy than we had. Facebook won't be a NEW concept to them. This notion of having all of your pictures shown to anyone won't be something that they have to come to terms with, or learn to deal with. It will be something that they already have come to terms with and already have learned to deal with.
And if the majority of your acquaintances are running around shunning people because they wear the wrong color or sing off key, then it's your world that I question. Not mine. Does that sort of thing happen? Sure, I guess. But only among the infinitely small minded, and only on issues that don't really matter to anything, such as who is going to win the next episode of whatever flavor of the month reality show is on at the time.