[sdan]

Interesting point. At the same time, if a person legitimately has an account (meaning it's their personal account) and decides to let everyone know of their entire personality, it won't be "pursuing an agenda".

But realistically, this doesn't happen; unless that avatar is anonymous and can't be linked to you. I think this is why places like Reddit and HN to some extent are good: they allow people to freely speak, but at the same time you're technically still being manipulated by what others think (on r/popular for example)... which brings me to my last point:

You're a composition of years of manipulation. It just depends on who you trust, whether it's in real life or online.

In all, I agree with your point, but giving anonymity brings people to talk more about themselves, which hopefully is a bit better than the world that you described is.