Then what is irrational? Rationality is defined by the society in which one resides. For example many people look at the middle east and see laws among numerous countries there as irrational, but that is because it is in comparison to our own set of rules. Politicians act irrational by denying that climate change is not a real issue when 99% of the scientific community agrees it is. In US society it is irrational to want to kill someone for no reason. In most place on the earth it is irrational to want to murder people. There is no rationality to mass shootings or mass shooters, so we cannot expect them to act in a rational way by any means.