Earlier quoted context omitted.
As has been pointed out elsewhere, PayPal has an explicit policy about how they handle presales. Why can't I turn your argument around and say that if somebody doesn't like that policy, the onus is on them to not use PayPal?
I don't grant your premise that crowdfunding constitutes "presales." Crowdfunding is an inherently speculative activity, a way to invest in a team with the hopes that they will create a product that you'd like to see in the world. Trying to fit Indiegogo into a presales model to justify PayPal's outrageous behavior here is a Procrustean approach that helps no one.
Crowdfunding is only popular because it's got a high success rate though. If only 50% of projects succeeded and provided rewards, and 50% took your money and ran, how many supporters do you really think would be left?