> multiple people at one of the companies mentioned saying that the reason payment processors don't work with porn companies is because of fraud rates.

This is a widely given explanation so I would entirely expect you to have heard it repeatedly in that context.

It is far less clear to what degree this explanation is accurate. Yes fraud rates are higher but they could easily be covered by charging higher processing fees (something that is often done for other risks.) There is pretty good evidence that other factors than fraud risk are at least partially responsible.

If you have an issue with people aaserting opinions as fact, maybe you should be more careful as you what you state as fact from a position of claimed authority.