I have someone in my family history that underwent electroshock therapy, and by all accounts was only traumatized and destabilized further by the ordeal. YMMV, I guess.

I remember reading the comparison, that all modern psychiatric treatments can be thought of as banging a misbehaving car engine with a hammer.

Sometimes it helps, if the hammer is hitting just the right place. Often it does nothing, letting the underlying disease to progress. And in distressingly many cases, it can harm patients.

This absolutely applies to the ECT.

So because the patient cannot recall the traumatic events, they're not thought to be experiencing that trauma, or taking lasting effect from it?

Yep.

That's also how dissociative sedation works. You don't remember being sedated, and you are not (psychologically) traumatized by medical procedures happening during it. I had it several times for minor oral surgeries, and it's great.

And the modern ECT is also done under deep sedation.

How long after the event do you think it makes sense for this erasure to happen? Like, let's say that you are going to experience something absolutely traumatic but you know next week you won't remember it... is that also ok?

Yes? You are basically describing every surgery.

Yes, those are taken far too lightly as well.

Not really though. Surgery typically uses anaesthesia that makes you not experience it in the first place, which is different than forgetting the trauma.

I don't think the human memory is well understood enough to say for sure whether consciously forgetting something means that there aren't still effects of your body having experienced the trauma in the first place. The mind, it would seem, goes deeper than conscious recollection, and perhaps beyond the brain.

Plenty of children abused before they can remember it still have exhibited signs of harm from the trauma.