it's actually an example of right-wing demagoguery, and something that should be attacked head-on - because at some point this needs to stop. at some point, republicans need to stop reversing this policy.
so, it's easy to argue that sanders walked into a trap like an idiot, but i actually think he's right.
the scare-mongering and alarmism is coming from conservatives on this, who want to frame the issue as one of totalitarian governments seeking out and terminating brown children. that's not reality, and not underlying any sort of actual government policy; if that is your concern, you should be more afraid of elon musk and bill gates than bernie sanders or al gore.
rather, the idea is that if you give women educational opportunities and reproductive autonomy then they will freely choose to reduce the number of children they have, which is something you see across the divide between the developed and undeveloped world.
in countries where women have rights, they tend to prefer to have less children. so, it follows that a way to get the population under control is to give women more rights. and, if conservatives have a problem with that, they need to explain why they're opposed to women's rights.
https://www.washingtonpost.com/politics/2019/09/05/bernie-sanders-abortion-population-control/