Do I think gay people post or comment on videos about the experience of being gay in a society that is often homophobic? Yes.

Do I think feminists post or comment on videos about feminism or rape? Yes.

Do I think transgender people post or comment on videos about being transgender? Yes.

Is there a subset of the above people that wouldn't want their YouTube activity known to their family or employer? Yes.

Reddit still exists.

No, but I might have previously liked or commented on a vlog by another gay or transgender person which is suddenly publicly tied to my regular Google account. Or I might have expressed a political opinion which isn't going to get me persecuted but might alienate a manager at work or a relative.

And yeah, there's ways of preventing this but they're pretty difficult to figure out (the Google+ page route) and it's fairly easy to make a mistake. Especially if they keep changing things.