bear in mind protest can be seen as a way to change a company policy. noone is saying paypal shouldn't exist, but personally i do agree they shouldn't be disallowing payments on behalf of wikileaks.
In this case, Anonymous will achieve making PayPal's website even slower for a while. If they lose customers it'll be for the wrong reasons. Anonymous needs to find a way to educate the public about a company's wrongdoings, not just disrupt the company's service while not making sure everyone knows exactly why that company's service has been disrupted. They seem to have this misguided idea that DDOS = public education and corporate humiliation. That's what I find shortsighted.
Anonymous has its own means and methods which you may or may not agree with.
If you agree that something needs to be done but think there is a better way to do it, then you need to carry it out, enough "armchair quarterback"-ing.