Well, that is assuming that the human race was meant for anything in the first place. I hardly think that everything has a purpose. Does one grain of sand sitting on top of another in a beach purpose as opposed to the reverse? Even in things that we know have purpose to us -designed things, we can see side-effects that do not have purpose. (or even counterproductive)
Guess that was a bit off-topic. For the rest i agree with DChristopher; except that technology by itself governed by perfectly reasonable humans could cause issues. (but i really do not know what to say about that)
@fluxy note that the question is wether mankind is suicidal as a whole.