I would more like to see why people blindly trust some group of human beings to not conspire, when there is every (often gigantic) incentive for that group to do so.

Yes but conspiracy theory as defined by whom? For instance, a critical examination of suggestions of such by uncited agenda-driven folk who work for social media companies, is recommended. Of course tons of nutty theories abound that have an exceptionally low probability of being true to any extent. On the other hand, a simple search reveals plenty of instances in the past where conspiracy theories, so defined at the time, turned out to be true.