Pilots were trained in how to deal with runaway stab trim. There were three MCAS incidents. The first one you never hear about because the crew followed the runaway trim procedure and safely completed the flight. The second one did not and they crashed. The third received an Emergency Airworthiness Directive that reiterated the procedure, apparently forgot about it, and crashed.

Yes, the MCAS design was defective. The crews didn't follow their training, either.