Originally Posted by AdultKing

Actually payment processors are completely liable for the actions of their customers in many cases.

Money Laundering
Copyright Infringement
Fraud
Obtaining Property by Deception
Obtaining Financial Advantage by Deception
Tax Avoidance
Aiding Terrorism
Funding Terrorism
and many other areas.

All payment service providers have strict Know Your Customer requirements in the USA and many other countries, these are in order to enforce such things as listed above.