I don't think morality has anything to do with HN's action/lack of action here. They are likely just balancing risk & reward.

How much work to enable auto paywall busting? >$0

How much reward? $0

How much extra risk that a publisher will make your life difficult, regardless of morality or the letter of the law? >0%

I can't imagine why they would bother when HN users seem happy enough to do the work for free.