This is all well documented in mainstream media, I certainly shouldn’t need to provide any evidence to a purported industry insider.
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.
This is exactly what happens, there are several payment processors (probiller, ccbill, epoch …) focusing on high risk transactions like porn.
What I am basing my statement off of is second hand knowledge from 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.
That's not definitive, but considering the person I was responding to gave us 0 reason to believe his statement is anything other than his opinion and his comment history shows a pattern asserting his opinion as fact. I'm going to assume he's talking out his ass and that I'm slightly more informed on this issue.