I think that that article is pointing out a nuance that doesn't apply. It seems to be saying that in 737 NG you had the option of disabling automated inputs to the trim system while not completely deactivating it so that you would be able to use the electric trim with the yoke buttons. My understanding of MCAS is that there is no way to turn it itself off so in order to disable it you have to turn off the electric trim completely, when there is really nothing wrong with the electric trim itself. The article misunderstands the elimination of the the option to disable the autopilots inputs to trim as the elimination of the ability to disable MCAS separately from from yoke button control.
What is interesting to me is why Boeing didn't tell pilots about MCAS. Quoting from another source that seems even keeled:
To counter the MAX’s lower stability margins at high AOA, Boeing introduced MCAS. Dependent on AOA value and rate, altitude (air density) and Mach (changed flow conditions) the MCAS, which is a software loop in the Flight Control computer, initiates a nose down trim above a threshold AOA.
It can be stopped by the Pilot counter-trimming on the Yoke or by him hitting the CUTOUT switches on the center pedestal. It’s not stopped by the Pilot pulling the Yoke, which for normal trim from the autopilot or runaway manual trim triggers trim hold sensors. This would negate why MCAS was implemented, the Pilot pulling so hard on the Yoke that the aircraft is flying close to stall.
It’s probably this counterintuitive characteristic, which goes against what has been trained many times in the simulator for unwanted autopilot trim or manual trim runaway, which has confused the pilots of JT610. They learned that holding against the trim stopped the nose down, and then they could take action, like counter-trimming or outright CUTOUT the trim servo. But it didn’t. After a 10 second trim to a 2.5° nose down stabilizer position, the trimming started again despite the Pilots pulling against it. The faulty high AOA signal was still present.
How should they know that pulling on the Yoke didn’t stop the trim? It was described nowhere; neither in the aircraft’s manual, the AFM, nor in the Pilot’s manual, the FCOM. This has created strong reactions from airlines with the 737 MAX on the flight line and their Pilots. They have learned the NG and the MAX flies the same. They fly them interchangeably during the week.
With that as background I do not find Muilenburg's explanation very satisfying:
"When you take a look at the original design of the MCAS system. I think in some cases, in the media, it has been reported or described as an anti-stall system, which it is not." Muilenburg told reporters shortly after Boeing's annual shareholder meeting. "It's a system that's designed to provide handling qualities for the pilot that meet pilot preferences."
Muilenburg added, "We want the airplane to behave in the air similar to the previous generation of 737s. That's the preferred pilot feel for the airplane, and MCAS is designed to provide those kinds of handling qualities at a high angle of attack."
"It's a purposeful design. It's something that's designed to be part of how the airplanes fly. So it's part of the certification process," the Boeing CEO said. "It's not something that's a separate procedure or something that needs to be trained on separately."
"It's fundamentally embedded in the handling qualities of the airplane. So when you train on the airplane, you are being trained on MCAS," he added. "It's not a separate system to be trained on."
It might not be a separate system to be trained on but why not just disclose the fact that it exists to the people flying the airplane?
Would you put the existence of MCAS down their with minutia that you don't really need to know like what size a piston is in a hydraulic system? It isn't a rhetorical question I am curious because I would think you would want pilots to know more rather than less.
