It's not "just to retain the same type rating" that the MCAS worked as it worked.
The MCAS, as it was implemented in the planes which crashed had to be implemented for the plane to pass the certification requirements which exist because of the safety.
The plane is with its geometry inherently unsafe without some clever devices correcting the "inherent" behavior.
Anybody who claims it's not "unstable" does misdirection of clinging to the technicalities of wording of the specific claim (as the plane can be technically-speaking "stable", if nothing unexpected happens, while still being the death trap under non-average conditions, and that's what happened here), as there are more elephants in the room remaining, to be specific:
- The regulation exists to provide safety.
- Boeing 737 MAX is unsafe to fly without some additional hardware and software which does the compensation. Nobody can sell or certify the Boeing 737 MAX as it is designed without adding some hardware and software that would do something similar to MCAS. "Just turning off MCAS" permanently or "just removing it" makes the plane non certifiable safety-wise, not only losing its "type rating."
- MCAS design (its power) wasn't decided only once and implemented. The set of events was that only during the test flights the additional problems with the safety of the plane's response to the commands were detected, and the MCAS revisions added more power to MCAS (and less to the pilots) through the time. The result was that the MCAS which exists on all the planes sold (and the planes crashed) is not the MCAS from the initial specifications or claimed by Boeing after the crashes, as they still quoted the original characteristics.
- The goal of Boeing of "keeping the same type rating" is the motivation why they decided to lie about what they implemented and why they actively reduced the safety of the plane to the point of plane actively being the death trap.
- Specifically, Boeing misused the trust it had: through the years Boeing was allowed to do more and more of the certification work for their own planes.
- Not to mention disastrous public claims there's nothing wrong with their planes even after the two crashes, a lot of information already public and most of the world already having grounded the planes.
- Not only Boeing lied about what they did to the FAA and the rest of the world, even after the first crash happened, but while making the plane the engineering decisions have been made more than once just with the goal of preserving the false promises made by the Boeing managers as they have sold the planes: that's why there was the change in the behavior of the switches where there were separate switches before but they changed two switches to behave identically, only to actively hide what the new MCAS was doing. That's why the system was made glaringly non-redundant: adding redundancy would make it obvious that the system was (and it actually was) critical.
In short, it's not misinformation that 737 MAX was a death trap made as such under the guidance of Boeing's managers.
There are many levels of evilness Boeing managed to achieve in designing the plane and responding to the existing crashes. Some managers should be prosecuted for what they did. If that doesn't happen, the laws should be changed to allow that kind of responsibility the next time, or there will be even more victims.