Ordinarily I would agree with you, but this issue of stability is clouding the truly detestable course of action Boeing took.
Boeing was trying to save money. They wanted to keep the same type rating, so they added MCAS to an inherently stable and flyable aircraft for purposes of retaining the same type rating.
The system they added included optional safety measures that airlines had to pay more to install [0]. Boeing new that MCAS would be safer with these features and charged more for them!
The true outrage here should be directed at this underlying cause and the erroneous discussion over stability should be put by the wayside.
It's like if I started to describe your app's database as "unstable" because your website's down due to cloudflare configuration.
(With that said it's all just petty semantics; we all understand what the post is trying to convey)