Amazon Web Services:

But, when companies or people go about securing and storing large quantities of data that isn’t rightfully theirs, and publishing this data without ensuring it won’t injure others, it’s a violation of our terms of service, and folks need to go operate elsewhere.

Removing WikiLeaks because they don’t own the data makes sense and is a common reason for removing sites. Removing the site though because Amazon can’t be sure it won’t cause harm to others is noble, but an odd thing for this type of company to enforce.