It's ironic that Y-Combinator's hacker news team stands up for so many positive internet movements yet feel that they can permanently keep all the content I gen

It's ironic that Y-Combinator's hacker news team stands up for so many positive internet movements yet feel that they can permanently keep all the content I generated. It is MY content after all. Do they own the copyright to MY words? The excuse has always been "it's a part of the public dialog". Am I understanding correctly that you asked (politely) by email to hn@ycombinator.com and they refused because "it's a part of the public dialog"? If so, I'm surprised and sympathetic. That response seems out of keeping with their generally accommodating approach.