The earth's carrying capacity is about a billion, if we also want to have wildlife..
At the same time we do this, we should find people who are doing good things, and encourage them to do more of them and breed more.
What happens in 500 years when the Earth is back to 7 billion? Another cull? Somehow, I think it would be a little more difficult the second time around.
That's the only way out of the hole that humanity's in. If we don't change our path, doom awaits.
What if there was another way? What if the 1st world, whose population is stable, moved more people into cities (leaving more room for the environment), eliminated CO2 emissions and other pollution, set strict rules on new development ie 75% of land is to be untouched, etc; and we stop trying to develop the 3rd world countries and let them live in harmony with nature?
Most people are too cowardly to change and fear change, so they're going to complain any time someone offers a solution.
Do you honestly think people are going to accept such a radical plan without first criticizing and probing it? Are your expectations of others really that low?