Why Anonymity?

It's probably another sign of my advancing age, but there seem to be more and more things these days that I just don't get. One of them is the penchant for anonymity on the net.

I find it hard to take seriously opinions offered by people who won't own them.

I have a vague understanding that the use of handles grew up with the net in its early days and never quite left. I also understand that true anonymity is largely an illusion and often not maintained with any vigor. So what's the point? I genuinely don't get it.