Libramarian
Adventurer
The concept of disassociated mechanics is not a theory of immersion. It's a type of mechanic that has a notable correlation to people complaining about loss of immersion. It's analogous to iambic pentameter verse in your example, not your theoretical explanation of the effect that iambic pentameter verse has on most English speakers.I quibble over "blames" as what is done to the person here, but that is just a quibble ...
I'm not sure that you can apply one word to this phenomenon, because I'm not sure that it is one thing that causes it, when it is caused, or that it is consistent. Plus, no doubt there are elements of human psychology, brain patterns, etc. here that we aren't equipped to answer.
Consider the esoteric case of metre in poetry, for example. It's known that iambic pentameter (five pairs of stressed/unstressed sounds) generally is perceived by most English-speaking natives to have a richer/stronger/better/pleasing sound compared to iambic tetrameter (four pairs of stressed/unstressed sounds). It's an objective fact that if you do a controlled survey of native English-speaking natives, you will find this strong preference. You'll get a non-trivial number of people who will report that iambic tetrameter is "sing-songy" or something similar.
Why this is so? I don't think anyone really knows, though I'm sure people have written guesses on it. The why is very subjective. Someone might be tempted to think that humans just like one better than the other. Yet, this isn't true, either. Reportedly, it does not hold for medieval French verse, which is often in iambic tetrameter, and does not generally produce a sing-songy vibe. Reportedly, there are similar differences in other languages. So the observation is something specific to those fluent in English--and usually adults, as children often like the sing-songy stuff.
So we can easily contrive fictional examples that will be more or less jarring, implausible, etc. to a wide swath of people, but trying to understand why is difficult. My objection to the (non-ranting, non-edition warring) parts of the TA essay has never been that it wasn't after something worth seeking, but that it settles for a too simplistic answer. Why does X rip Bob out of immersion completely, Larry a little, and Shemp not at all? That's a good question.
Edit: What I'm talking about here is the difference between characterizing a thing versus a tighter, more explanatory definition. If you want to characterize what this thing is in a word or phase, I think you can't beat "immersion breaking" or "breaks immersion". It's true, unobjectionable, clear, etc. If you want a word or phrase that explains why it happens concisely and objectively, I don't think there is any such animal.
The concept of dissociated mechanics is extremely useful to the designers of 5e, who want to please people who complain about loss of immersion (and they have mentioned the concept a few times in blogs/articles). A full explanation of the effect is not required for that purpose.
I think some of those who want to ban the concept really just want to shut out the influence of those who value immersion on the design of 5e. i.e. they're analogous to people who don't get the richer/pleasing effect from iambic pentameter verse, so they want to destroy the concept to make it more likely that poets will use different styles. That would be pretty unfair. Everyone's desires should have a chance to be articulated. People should focus on articulating their own preferences better rather than attacking others' ability to articulate theirs.