It generally means freedom from government consequences. It also generally means that third parties won't actively prevent you from speaking to people who choose to listen to you.
Unless people decide to pressure the third party into de-platforming someone, which is their freedom of expression. I don't understand why the free speech absolutists on HN are incapable of understanding that private citizens pressuring a company to take action against a hate site is equally as much free speech as the hate site itself. By your own standards, nothing objectionable is occurring here. They just want to be contrarian.