This one is pretty self-evident. No, there's no "freedom of speech" issue involved here; Substack is free to choose what it will or won't platform. But even if it was interested in platforming them from a misguided devotion to “not censoring”, there’s no reason it should be profiting from them, or helping Nazis profit from it.
That’s a choice. And it’s the wrong one.
As a palate cleanser, enjoy a few videos from Pexels