From what I understand is that the comparison between cruise control and MCAS breaks down when it comes to how quickly the potential catastrophic situation may

From what I understand is that the comparison between cruise control and MCAS breaks down when it comes to how quickly the potential catastrophic situation may happen. When driver steps on the brakes -- the system disengages and car slows down. When pilot disables MCAS -- the system disengages and the plane is more likely to enter aerodynamic stall and crash. So with cruise control there is no potential for catastrophic positive feedback loop when the system disengages, whereas MCAS needs to be pretty aggressive in what it does.