[stonogo]

Having dealt with this in the past, once you let cryptocurrency people onto a service they will stop at nothing to abuse shared resources for whatever mining fad is currently underway. As an operator, you can either hire staff for a full-time whack-a-mole game, get into arguments with customers about whether what they're doing is shitty even though it meets some pedantic interpretation of policy, or just ban the whole crowd and focus on customers who don't suck.

As for banning sex content on a paid service, you'll find it's more common than you think, since payment processors tend to drop customers who permit that sort of thing. Porn-enabled services have chargeback and failed-charge rates orders of magnitude higher than services which forbid them.

There are a ton of reason to fire a client. The two mentioned here are completely uncontroversial from a business standpoint.