This is why these platforms won't be a "marketplace of ideas", ever. There's a certain differences between a public and providing a platform as a private enter

This is why these platforms won't be a "marketplace of ideas", ever. There's a certain differences between a public and providing a platform as a private enterprise, and chances are that the commercial interests won't align with what maintaining a public or a true representation of it may afford. (BTW, HN is doing a great job in providing a platform to a specific public. But this is only, because HN is not the primary source of income for Y Combinator. Rather, this is a strategic investment, which happens to strategically align itself with the interests of this specific public. But I doubt if this could serve as a general blueprint. And it could be gone in a moment.)