I wish it was this simple :^)
Consider Facebook, where people post mostly under their own name and photo. Even a casual visit to Facebook quickly reveals your hypothesis is wrong; it's nearly the exact opposite of reality.
Contrast that with HN, where users range from pseudonymous to fully anonymous, and where discussion is kept to a much higher standard.
It bears repeating - the discourse on HN is kept to a much higher standard. Active moderation and community guiding, performed by intelligent agents, is the real answer to the woes. Anything automatic, anything with a guaranteed outcomes will be 'gamed' and put to bad ends.
--edit--
There's also the separate but equally important matter of privacy. As internet spaces became both the town square and also gentlemens' clubs and also private homes to multitude of discourses, we need privacy from various actors' prying eyes.