Historically, hn etiquette is that it's fine to downvote for disagreement. This came from pg himself.

That said, while he hasn't posted here for a long time, this is still in the guidelines:

> Please don't post comments saying that HN is turning into Reddit. It's a semi-noob illusion, as old as the hills.

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