Name three academic institutions that would sign a contract that prevented them from publishing adverse results. You are at least fifty years out of date on this argument.
A) They don't have to have that in writing, it's very implicity understood that you don't bite the hand that feeds. B) Even if they do find adverse results, depending on what they are (e.g. actively harmful versus negative results) you may have a hard time publishing them since journals don't care much for negative results.