So? Thats free publicity. If they something bad about you, all they're doing is informing people of your existence. People will judge for themselves whether you are worth using, usually by checking it out themselves. At least, the kind of people you want on HN will.

The problem isn't with them badmouthing you on your site, it with them polluting your product. If the product sucks, people won't use it, no matter how much you suck up to them.