That's true, but the question might be whether you personally should be worried if you find yourself on a 737 Max.
Incompetence is understandable, improperly modeling the physics due to lack of experience or knowledge is understandable, but repeated instances that point to corruption at the government regulator and bad culture at the manufacturer lend to fears that the situation will get worse for a while before it gets better.
It’s the same reason you might avoid flying on an Eastern European/Russian airplane. The perceived risks move from unforeseeable error or bad luck to systemic error.