I think most of what you said is indeed, generally true.
However I don't think it's limited to TMA, I think it's just easier to get worse results in TMA because there are so many layers that are totally useless if you are not instructed in what they are for, and they are just done as busywork "just because". If it would be like if someone taught you how to hit a speedbag and never explained how to properly do it, or what it is supposed to accomplish.
This is what you see with a ton of mainstream TKD and Karate, and you are right that the results aren't pretty.
Can't we just understand that we are speaking generally and that exceptions exist without having to do this every single time?
Not really, because the context of the thread is the usefulness of this method of punching, and that is only possible for people who understand what it is for in the first place. Clearly if someone goes to a "just because" school, the question of usefulness is already answered!