The devil lies in the details. Who should be spayed, and by what criteria, are pretty important questions. And if you grant this power to government, will it be misused by power hungry bureaucrats? Almost inevitably.
What is absolutely true, though, is that letting pederasts, retards, and niggers without impulse control procreate, creates massive problems for the next many generations. Every generation from now on, will be a generation with more stupid, violent, perverted and mentally ill undesirables. It will assuredly lead to some kind of breakdown, like France, Detroit or San Francisco.
In fact, the only redeeming things about troons, is that they solve the eugenics problem by self-sterilising. I despise troons as much as the next man, but I do admire their fight to remove themselves from the genepool.