Despite the fact that stamping currency is entirely legal -- which PayPal does not dispute! -- I've been forced to stop using their payment service to sell Tim Geithner "Tax Cheat!" stamps. There's no doubt in my mind that they shut me down for political reasons, because nothing I'm doing violates PayPal's Acceptable Use Policy in any way.
They're a private company that can do what they want, but I think that whatever low-level employee made this call is way out of line and is acting disgracefully.