What causes HN accounts to be rate limited?

I have seen others mention their account being in this condition and didn't know what they were talking about until it started happening to mine.

I'm frequently blocked from commenting on articles due to a "you're submitting too fast" for hours after submitting 4 comments or so. This seems to be new behavior that started a few months ago after I expressed some unpopular opinions.

What are the criteria for being muzzled this way and is there a way to get it removed? Or is the position that systematic oppression of dissenting views is better than the disruption they may cause?

I'm aware we're not supposed to break the fourth wall and discuss these topics, but this seems to be a pretty hidden level of damaging censorship (I frequently can't even reply to replies) of which most most users are unaware.

What is the desired message moderators want muzzled users to receive? "go away"?