If I used Amazon, I wouldn't boycott them for their choice of applying their TOS as they see fit, in order to remain solvent and profitable. Any product or information that is inflammatory or controversial falls under their right to deny hosting. If they decided to host the data in spite of a government "request", they would have to expend vast sums of legal resources and manpower when the shitstorm hits, and that is an unprofitable situation. They are in the business of making money. Not losing money.
The Wikileaks guy has other avenues to pursue in order to keep his data online. He has no right to expect Amazon to take a bullet for him. What has he offered to contribute towards their troubles? A $4.95 processing fee? Fuck him.