While I haven't dug really deeply, I don't think the situations are directly comparable. Adult businesses aren't banned at the federal level, and as long as there's no state law that bans them, there's nothing that
legally prevents them from opening a bank account, processing credit cards, and so on.
The problem appears to be specifically with the policies of payment processors. As I understand it, the actual payment processing networks -- MasterCard, Visa, et. al. -- historically charged a significant premium to process transactions for businesses that had a reputation for very high chargeback rates (people calling to cancel payment). Adult businesses had that reputation. From what I've been able to tell, this has persisted to today. It's presumably just easier for payment processors like Stripe and PayPal to ban adult content than to work out multiple rates with their credit card networks, let alone try to make the (correct and I would argue obvious) case that Patreon, Buy Me a Coffee, Ko-Fi, et. al. aren't "adult businesses" even if they allow legal adult content creators on their platform any more than Amazon is an "adult business" if they let you buy books with explicit content.
That's a point I've always wondered about, actually; Amazon does let you buy books with explicit content, both text and visual (a search for Erika Moen's "Oh Joy Sex Toy" right now immediately showed it was available both in paperback and on both Kindle and Comixology!), so it's clearly not as verboten as the crowdfunding platforms make it sound. I know Amazon has the advantage of being Amazon -- MasterCard isn't gonna stop processing their transactions no matter what they sell -- but I also know a few very small publishers who sell erotic comics and that use Stripe and/or Square for payment processing. Again, those publishers aren't really "adult businesses," per se (not all their titles are adults-only).
I would really like a processor like Stripe -- or a competitor, but I suspect size matters in this case -- to step up and not ban legal adult material. Maybe even just in small steps, by explicitly exempting publishers or crowdfunding platforms that aren't exclusively adult.