What's the difference between this, and e.g. https://en.wikipedia.org/wiki/Eye_movement_desensitization_a..., or use of propranolol together with therapeutic hypnosis to recall—and then block/degrade—fear memories during reconsolidation?

In all three cases, you've got a specific "associative" pathway that's bothering someone and interfering with their lives, that they seek out treatment for; and in all three cases, the solution is to get their brain to just not activate that specific association any more, in effect just ripping/burning out the synapse that causes a memory of X to in turn activate emotions or memories of fear/shame/trauma/etc.

I say "in effect", because the brain is electrochemical; and so it wouldn't seem to matter whether you blow an association away at the electrical level (by e.g. physically removing/necrotizing/calcifying the synapse-as-"wire", as ECT does; or by increasing its "resistance" by reorganizing it at a molecular level, as TCM probably does), or you do it at the chemical level (by e.g. re-training nearby junctions so the "carrier signal" feeding into the synaptic junction is too "noisy" to pass signal along, so even if the path activates, descending connections don't receive useful information from it, and so learn to ignore it; and/or by temporarily starving/blockading the ion pores it uses to receive voltage-generating ions through, starving it of its ability to work as a transistor for the signal it wants to generate—until, again, descending connections learn to ignore it, even when it comes back fully functional after removal of the blockade.)

But, as a separate ethical argument, I'd like to also point out: people do, obviously, have the right to self-modify their neuronal architecture. They must be fully informed and consenting as to the consequences of such, and must want those consequences—think them better than the alternative, than all alternatives. But then they should be allowed to do so. And, since they—as lay-people—can't do so by themselves, trained specialists should be there to help them to safely perform the modification they want to perform.

That's the same bar that a patient already has to pass, to qualify for e.g. hormone-replacement therapy targeting gender dysphoria. Medicine already has an infrastructure for ensuring patients want what they want, here. And that infrastructure (mostly coincidentally) already prevents doctors from just deciding to do these things to patients without the patient putting in the effort themselves to go through this "one thousand consent forms over a space of months" rigamarole.

(Many people might say, in fact, that the existing infrastructure sets the bar too high—for example, that doctors make demands of patients to prove specific preferences over desired outcomes of treatment that align with the "on-label" use of the treatment, rather than accepting patient requests to use such treatments for their well-known "off-label" effects. In the HRT case, many people who identify as non-binary want to get HRT for their own reasons, but some doctors don't want to give it to them, because it's only indicated for a specific kind of gender dysphoria related to wanting to achieve a clear end-state of a binary gender.)