You are right, power is not a super natural force. However, the psychological impact of power is very real and well understood. The evidence of our own experiences should be enough to tell you this. Also, there are countless psychology experiments demonstrating the corrupting influence of power, which often boils down self-preservation through a continued hold on power. People will make up any old bullshit to justify why they should in power.

The degree of corruption varies between individuals and the level of responsibility they have, but once you bring people into groups it becomes unavoidable. Public transparency and oversight is about the only thing that can constrain it.