Something I don't understand

So, I've heard the theory that ET's will stop humanity should we become too violent or too dangerous, explaining the reports of activity at nuclear weapons sites. What I don't understand, is if different world governments know this why are so many world leaders, especially in the US, blowing up alliances and escalating the violence in the world? Why would they try to provoke these beings into wiping us out? Thanks in advance, trying to make sense of a world that doesn't make sense. submitted...