This article seems to focus on things from a perspective of things from a small plane pilot. So a little wider perspective might be helpful.

A 737 first off is not a Cessna like the author mentions flying. You do not get to use direct inputs easily nor do you want to have to fight stab trim because the force on the stabilizer control surfaces is muuuch higher than those on a slower flying plane. Because of this, when the 737 came out there were designs for trim systems that can help. These systems work by adjusting the trim settings for pitch using motors (like the author mentioned). However sometimes these systems would give erroneous inputs to the trim. The system might be causing incorrect trim up or down depending on the failure. This is officially known as stabilizer trim runaway. The procedure for this has been well established as a memory item meaning all pilots of 737s must be able to correct this without referencing a checklist since it is so dangerous. And it is HARD to correct because of the aerodynamic forces on the stabilizer. You can find videos of training for it. Now they introduced MCAS. A system designed to adjust trim automatically to compensate for the shift in the moments acting on the plane due to powerplant placement, etc. This adjusts the trim as well to prevent to high of angle of attack that would allow these different moments to introduce a stall situation. So what procedure should you use if it starts giving incorrect inputs? That's right, the stab trim runaway procedures, which again should be a memory item all pilots of these 737s should know and be ready and able to execute. The differences between systems that cause it just means you are taking different systems out of the control loop. This is also why I believe the FAA said it was fine to forego full airframe certification requirements. The procedures for handling the plane just didn't change drastically enough.

Yes there was negligence on Boeing's part, but I also think it's worrying that the reports seemed to indicate that the correct procedures for runaway stab trim were not followed which could have saved lives (e.g. turning MCAS back on while dealing with runaway stab trim). Also something to note is the plane in Ethiopian airways' crash was flying with "unusually high thrust settings". Remember the aerodynamic forces that make runaway stab trim a bitch to deal with? Well those forces get stronger with more speed. People are quick to point the finger at Boeing and surely they ARE at fault in some ways, but what's worrying to me is that there are pilots that are being trained that cannot perform the proper procedures that have been known since way before MCAS. Whats more is that the motors for trim from MCAS is limited to move at a rate of 2.5 degrees over 10 seconds with a pause of 5 seconds before the next adjustment. This is definitely slow enough to give pilots time to catch the runaway trim, cutout the stab trim and regain control. Anyway I am just surprised that the engineer, working for Boeing, couldn't be arsed to also give this info which allows an alternative perspective. It is bad that stab trim runaway is happening more with this system and Boeing acknowledged it and pushed patches. It is worse imo that pilots are forgetting or just not being trained on how to recognize and correct for stab trim.

Edit: Any details or numbers about the systems I got wrong please post a comment so I can correct it.