The first amendment does not cover private entities like substack. It is very challenging for a platform like substack, more challenging than first amendment protections, which can be pretty wide. This issue has been ongoing since the internet began. Content moderation has been an issue for every platform. Except for a few, like 4chan or 8chan, it has existed on almost every platform that is widely used by the public. However, because there is a faction in the US that is favorable to extremist ideas like Naziism, which is certainly a genocidal program, and because they will attract dollars, it appears substack is going to let various stormfront bona fide Nazi substacks to exist. This is indeed allowing the platform to become a venue for genocidal ideas. I am simply stating in clearly. People who favor mass violence, expulsions, and genocide will have substacks where they argue for ideas which will make arguments that promote these ideas. I would love to see an argument where allowing people with genocidal ideas an easy way to reach an audience is somehow preventing genocide? That seems to be your view. I think it is quite reasonable to disagree with this view, and you have simply provided no argument for it.