I agree that the medical insurance industry in the US is extremely dysfunctional (in large part because of regulations), but people have much more recourse when they are harmed by an insurance company compared to a government agency. I doubt more people die as a result of insurance companies decisions compared to the FDA's decisions. I can't find a good estimate for the number of deaths caused by insurance companies, one study from 2009 estimated 45,000 deaths annually linked to lack of health coverage in the US (these would be more comparable to those who die because of the FDA because they similarly lack recourse)[0], this is probably much lower than the FDA's death toll. FDA was also likely a contributing factor in the deaths of many of those who died due to lack of health coverage because the FDA's licencing costs and the slow and arbitrary way it processes applications are a significant reason for the high drug prices in the US.
[0]: https://news.harvard.edu/gazette/story/2009/09/new-study-fin...