You really think cyber terrorism is going to make Mastercard more likely to want to work with similar groups in the future?
If they continue to choose to ban payments through their system to Wikileaks, I assume they'll continue losing money from DDoSs. shrug I don't have any idea what'll happen, but I think you have to accept that Anon has a point, even if you don't agree with them.
MC slows the flow of information. Anon slows the flow of cash to MC. If MC doesn't respond, it seems like they'll keep losing money.
And I think the answer is no, although it's arguable. There is surely a point at which MC will try to do the "right" thing instead of the profitable thing, and it's easy to see how that point is between cutting off Wikileaks (which arguably is harming US national interests) and changing business strategy to appease hackers.
Given that its unclear to me that what Wikileaks even did is illegal (http://www.nytimes.com/2010/12/02/world/02legal.html?_r=1) I have little sympathy for MC. It just feels like they're a bully in this situation. It does suck for their customers though. Maybe more customers will drop MC due to their inefficiency? Who knows.
If I worked for any sort of internet payment gateway, I'd certainly make sure to never take on Wikileaks as a client.