Indeed, the problem is not that some companies choose not to do business with Wikileaks (which in and of itself should be perfectly acceptable), but that those companies represent such a large portion of a particular field that they are essentially shutting Wikileaks out.
Be that a good thing or a bad thing in this particular case, this gives the impression that influence peddling, threats and bribery have replaced the Rule of Law. This is not acceptable under any circumstances. If we believe that no-one is above the law then the same applies for ideas and ideals. There can be no morally superior principle that is above the rule of law.
The rule of law has been a cornerstone of democracy (and other systems of government) for over 23 centuries. It would not be an overstatement to say it is a cornerstone of civilization. I cannot see how it can be removed.