Why Is the Human Race Trying To Extinguish Itself

Why with the proliferation of nuclear arsenals of a global scale it seems as if it's inevitable. Someone eventually has to drop another nuclear bomb. It appears that it's only a matter of time. Why else would there be so many scattered around the earth? Not to mention all of the Wars that continue on & on. You would think that human kind would smarten up and put an end to all these atrocities.