https://www.paypal.com/us/webapps/mpp/ua/acceptableuse-full
They're well within their rights to decline your business. If a bank told the government, "We have no absolutely no idea what our customers are doing with their money or who they're sending it to. Maybe they're sending it to terrorists or drug lords, maybe they're not; it's none of our business and we respect their privacy", they'd get shut down in a heartbeat.
I can understand if Paypal doesn't want to appear on the front page of the news for funding an underground child porn ring that signed up as one of your "enterprise clients".