Re: Was altering Kurn's memory "Kahlessian"?
I'm more concerned about the fact that Bashir went along with it
Doctor Crusher erased someone's memory on two or three occasions (or tries too) without the person's expressed permission. So it's apparently not against Starfleet medical ethics.
Deanna Troi routinely looks into peoples minds and then announce when she discovered there to the entire room, hows that for a violation of medical ethics?
It's easy to support someones beliefs if they are identical to your own.
Tolerating beliefs that you don't personal embrace, or even fully understand, is harder.