Is this a serious post? The government can exact capricious petty revenge on your business, so it's not the business's fault for exercising cowardice?
It would be unbelievably easy to rightfully Godwin your perspective on this issue, but I won't do it.
The United States is a nation predicated on a set of inviolate rights that are supposedly protected by the charter document of the nation itself. Among these rights are the right to hold property, conduct affairs freely, and speak freely. The courts have repeatedly defined rights that are derivative of our constitutionally-protected ones, and that among these are the ability to conduct business free from the threat of arbitrary governmental coercion( e.g. absent of a "chilling effect" ), with obvious exceptions made where the business has committed a crime.
PayPal, Amazon, et. al. Have not broken the law by providing services to Wikileaks, and are, therefore, not in danger of retribution by the government specified in the US Constitution. The salient point here may be that the government we have is possibly NOT the government specified by the US Constitution, and these companies ARE in danger of capricious revenge by the government. And if this is the case, we as a nation are living under the thumb of a truly illegitimate government - and we have bigger issues to worry about than the cowardice of companies.
But whether or not we exist in a nation of arbitrarily exacted State power, nothing changes the fact that Amazon and PayPal are corporate cowards, in the absence of an actual, honest-to-god court order. To say they should be held harmless is, well, an "interesting" perspective.