Not all user generated content is the same. Some of it attracts more attention, some of it less. The site operators have a great deal of influence in determining what shows up. You could use HN as a pastie if you wanted. But I imagine if it started causing trouble, pg would enact measures to discourage such use.

I admire the people willing to fight the good fight, but it doesn't seem like the guy running pastie.org has any skin in the game. It's easy to decide you're going to run a laissez faire type site when you don't pay the bills.