I don’t believe this author understands the issue here. His description of the force feedback on the wheel is not correct. The automatic trim adjustment from the MCAS would not be detected if the pilot is trimmed in and at neutral stick. They may detect the pitch change and pull up/retrim for level flight, which disables the MCAS temporarily and gives the impression that trim is under control.
The author understands the issue fine and their description is correct. MCAS is a trim-and-feel system that exists to satisfy the stick force gradient requirements of 14 CFR 25.143 [1] within a relatively normal flight envelope. A stick pusher is a stall warning/prevention device that exists to satisfy 14 CFR 25.207 and 25.103, and which doesn't activate in a normal flight envelope.
The author does not say say that MCAS works as a stick pusher, and does not describe it as if it did. He writes "When the AOA reaches a point without enough stall margin, the system adds some nose-down pitch trim. That pitches the nose down and gives the pilot the stick force to know that he is pulling too close to the stall margin" [my emphasis.] Given that the trim operates by changing the angle of incidence of the stabilizer, and apparently only provides feedback at the yoke through the aerodynamic consequences of the trim change, is that inaccurate is some way? Maybe the threshold is as much one of stability margin as stall margin, but that's not significant with respect to the issue here.
