> Hacker news is there to promote ycombinator companies. So long as you know and avoid this it's surprisingly high quality. But that's there to lend more ligitimacy to ycombinator.

Everything has a cost. For the web, that's typically monetary or your data and attention to advertisers. I think you're right that the cost of Hacker News is that my participation is lending some (tiny incremental) legitimacy to Y Combinator. It's also costing some tiny amount of my attention, in the sense that I may not have heard of Y Combinator if it weren't for Hacker News. For me personally, that is absolutely fine – but I'm glad you made it explicit so that it's a conscious choice.

[Edit: Of course it costs an absolutely vast amount of my attention :-) but I mean only a teeny tiny fraction of that is "payment" in the sense of noticing that Y Combinator exists.]