From the guidelines: "HN is a community—users should have an identity that others can relate to."

https://news.ycombinator.com/newsguidelines.html

Reputation and past statements are useful tools in analysing people's beliefs and arguments and the reasons they make them.

Fully anonymous commenting creates certain incentives and you can see those at work on 4chan. There are good points and questions to be had there by anonymous posters but it's a more difficult exercise in finding and parsing them.