The problem with revolutionaries fighting for a cause is that they tend to forget that in order to progress THEIR agenda, they run the risk of becoming the OPPRESSOR.
Not everyone shares their opinion. Not everyone thinks what Mastercard or Paypal or even the Government has done is wrong.
See, these things are not always black and white. To be for something, you must also be against something that others might be for, thus you must place YOUR beliefs over someone else's beliefs. Just because YOU think you are right doesn't mean everyone else must be wrong by default. We are all entitled to our beliefs.
This is where Anonymous has made their mistake. They attack businesses for deciding to REMOVE themselves from a situation. Mastercard didn't do anything to wikileaks or Assange other than to distance themselves and cut ties. So what is accomplished by attacking their website other than to make yourself look like a bully who will attack anyone who disagrees with you? Then attacking the FBI for doing their job? You're just starting to look like a bully at this point and if Anonymous doesn't tread carefully, they will become that which they hate; bullies that rule by intimidation and fear. "If you are not with us, then you must be against us" has always been a failed mentality.
Of course, the assumption is that anyone who works for the government or a corporation is "evil." That is the biggest problem I see in these situations, because this assumptions is incorrect. A lot of people who work for these companies, governments, law enforcement groups, etc are actually decent people just doing a job, maybe doing something they believe in. Some would say that nobody is truly innocent, but I prefer to believe that not everyone is decisively guilty by association.
At any rate, Anonymous is seriously overstated right now anyway. Sure DDOS attacks are annoying, but for the most part it boils down to a legion of script kiddies playing at "revolutionary." Most don't expect or anticipate the consequences they could face, or the reality that they might be harming others or the potential punishments they could be hit with. It's all fun and games until you are 15 years old with an arrest on your record, the label of being an anarchist or extremist attached to your name, and sitting in a jail cell somewhere being asked very tough questions by very serious people. I'd wager a good part of Anonymous wouldn't find it as exciting under those circumstances. But then again, very few of them I'd wager have the skill or desire to take things to the next level beyond bringing down a website here and there in protest.
The worst thing of all is that all they are going to accomplish is to make life harder for honest, decent hard working people like you and me. I enjoy my freedom of speech and such on the internet as it is now, and I personally don't want a bunch of kids making things more difficult for me to surf the net or argue on forums or limiting my internet accesses by stirring up drama. Because THAT is the more realistic outcome... the majority of people aren't going to take up arms against the government, they are going to BLAME anonymous. And when that happens, they will deserve every bit of backlash they get.