Everyone has their own reasons because people are trying to simplify things down to just a couple of variables. The problem is that there are many variables all

Everyone has their own reasons because people are trying to simplify things down to just a couple of variables. The problem is that there are many variables all tied to each other in complex ways which just can't be simplified that much. You can't just look at one action, no matter how large, and claim that it was bad because of a problem it caused. The relations between all the variables means that a different action or inaction may have ended in the same problem coming about via an alternate path of cause and effect.