MCAS was used to make the aircraft conform to the regulations, it could not be omitted. It is intended to increase the control force at a point in order to as

MCAS was used to make the aircraft conform to the regulations, it could not be omitted. It is intended to increase the control force at a point in order to assure control forces steadily increase into a stall. (See 14 CFR 25.203 -- Stall characteristics. (FAR 25.203)) The fact that it was not communicated in the training and manuals was a result of lobbying by the airlines.