All these bullshit things like making greener cars or eating less meat or becoming vegan, why dont we just kill a shitload of people. That would take care of the problem real quick.

Indeed, eventually in the long run the population will almost inevitably come down unless we find some miracle of a way to get of this planet. As shown with the one child policy in china, population control is very unpopular and that was just limiting births not killing people.