The industry is rife with this kind of fraud, and chargebacks represent tangible risk of financial loss, so banks just blanket ban working with certain industries.
People who sell precious metal jewelry for credit card payments are another.
source: used to run porn websites back in the early 00s.
The banking services they terminated consisted of a single business checking account, business savings account and company credit card. That was it. That was what they deemed "too risky."
We learned from someone who used to work at Chase's compliance department that most big banks just have a flat-out ban on working with any customers that are involved in the industry in any capacity what-so-ever due to concerns over serious things like human trafficking. It was the fact that we were distributing [lawful and traceable to the producer] content that made them not want us as a client.