Sure, but that equally applies to companies following the money when they de-platform somebody over public or internal outrage at being associated with or enriching them. The point is that Substack's market position as "place where you can tell your truth after you get cancelled" is inconsistent with the purported motivation of a higher, abstract ideal or value of free speech. It's consistent with wanting to make money, and it turns out that the stuff that might get you banned on twitter can make a lot of money elsewhere. When the ideal of free speech (can I post porn there?) clashes with the ideal of making money (what if corporate firewalls ban us and our emails go to spam?), the money is preferred. There is no reason to believe the content currently protected there today would remain protected if the financial motivation shifted.
I think it's beneficial to be specific about what you're advocating for and what the problem is. What you expressed is that they are actively censoring sex workers for just being sex workers. If they've taken a moral position on that, but not other things then you're right - they're guilty of selective morality and their statement is moot. If on the other hand, they're censoring images and videos but not stories or identities then that's a different ballgame. In that case, the problem doesn't lie with Substack it lies with other institutions that likely have a lot of influence over Substack and may take time and strategy to overcome. As a long time champion of privacy and anti-censorship, advocacy is not some zero-sum game rife with pots of reductions to strong arm people and institutions into what you want. It's about understanding the root of the problem, which likely was formulated in good faith at some time, and trying to course adjust it to fit our world today.
