For those keen on quoting the longitudinal static stability requirements of FAR 25.175, Should note that the device in question is MCAS, ie manoeuvre, not static.
It is clear from the early descriptions of the MCAS it was about stick forces during manoeuvre when approaching the flaps up stall.
I suggest you look closely at the approach to the stall requirements of FAR 25.203(a). The STS system looks after any static stability problems.
The problem is in interpretation of these certification standards.
Many years ago stick force lightening, on the stall approach, was accepted by the FAA, provided the stall characteristics were otherwise found to be compliant The British ARB had a different view at the time. Hence stick nudgers were required in some British certificated aircraft which were not required in FAA certiicated aircraft.
It now seems any tendency towards stick force lightening is unacceptable to the FAA. I haven't looked recently but don't think the written rule (concerning longitudinal control approaching the stall) has actually changed from CAR 4B circa 1953.
At no stage during this thread has there been any force value given to the extent of the manoeuvre stability non-compliance of the B737 MAX 8. Don't forget that as little as 1lbf would be a non-compliance and would require a "fix".