Is apathy our greatest weakness and the root of everything bad in human existence?

I would say sick Pride or toxic pride, (by the same meaning).

Well, as Chairman Mao put it, laziness is the grave of life. Very true.

It’s the root of the inevitable demise of human existence

Apathy is weakness I agree but it is not root of Everything bad in human existence.

If human stays in his own whether he do nothing then it's not bad. But If he tries to harm others by indulging himself in others life then it is evil.

Apathy is certainly one of man's many shortcomings yes.

Who cares..?