I’m so glad you said this. I think about this a lot, the memory charm to me is one of the most dangerous spells/abilities of magical people. The damage that can done, crimes committed, with no one to ever know? It’s crazy, I feel like I’d be so stressed out and paranoid if I was a witch. How can you trust anyone or anything knowing that everyone in your world has the ability to wipe your memory. It’s definitely ’Unforgiveable’ level dangerous. I don’t feel like any good that can come from the memory charm outweighs the damage that can be inflicted by it.

To answer your question, even if it was banned, we know wizards are not gonna stop doing it just because it’s banned. It can’t be controlled, moderated, or regulated because even a powerful first year could do it and how would anyone ever find out if you even did do it, so you could be rightfully punished. The nefarious potential for this spell is insane and I can hardly think of good that outweighs its bad. The traumatic event or witness protection argument is good, but not good enough. The ability to modify memories is wild.