> my impression of the Substack stance was that it boiled down to "one of our main values is free speech, and while we understand the desire for content moderation, we're going to lean towards letting people use our platform even if we disagree with what they're writing".

You have a bar, and you let anyone come in and say whatever they want, because you like free speech. At first it's just a normal bar. Then the local Nazi gang finds out about it, they show up and start saying Nazi shit to everyone. Everyone else stops coming because they don't want to hear Nazi shit, so, it's a Nazi bar now. The only people there are Nazis or people who don't mind drinking with Nazis. You say you aren't a Nazi, but you own the Nazi bar.

Substack is the Nazi bar.