I have nothing against the author of this article. I do have something against Substack. It really is that simple. If this article is posted somewhere else I'll read it.
If this Lemmy instance had a bunch of Nazi content and the admins said they wanted to keep it up, then I'd block this instance. I wouldn't try to rationalise it by saying "oh well it's not like all the content is Nazi content..."
Again, it really is that simple.
If you're fine with supporting a platform that welcomes Nazis with open arms, fine, you do you. It's a personal choice.