Free speech is only protected from the government. To a certain extent companies and individuals are barred from some types of actions that would prevent your voice from being heard (in the literal or figurative sense). But no company is required to permit all speech via their forums or by any individual person. HN is hosted in the US, but actively attempts to block spam content. Is that hurting the "free speech" of the spammers? Sure, if you're into that sort of thing. But HN has no obligation to give them the opportunity.
I'm continually amazed at how people can't understand this. You have a right to not have your free speech stifled by the government, but that has nothing to do with what a private corporation decides to let you do with their product.
