That's not typically how people operate though. When you go to your crazy culty church or your Socialist Workers Party meeting or your gun club or your polyamory potluck you don't typically go by a pseudonym, you just don't expect your work friends and your church friends to overlap, and if they do, who cares, your friend was at church too. The problem seems to be reconciling this with a world where you can google for people or add them on social networks where all these disparate things happen online. But even then, there's a simple solution--don't use social networks. Sign up for the gun forum, the polyamory forum, the culty megachruch forum, the Socialist Workers Party forum, and even if you use your real name or a traceable pseudonym, people would have to go out of their way to match things together, and with a lot of false positives along the way.