What's wrong with 'population control' through easy access to birth control and lowering infant mortality? Do you think he was planning on mass killings before

What's wrong with 'population control' through easy access to birth control and lowering infant mortality? Do you think he was planning on mass killings before he realized he should be more subtle? He's not a superhero, but it's definitely better to devote your capital to helping others rather than simply accruing more.