Certainly if "ethnic cleansing" is used to mean "genocide" it is a euphemism. But I don't think that's what the term was invented for.

I believe "ethnic cleansing" properly means the forced removal of an ethnic group from a geographic area. By that standard, what the US did to Japanese-Americans from the west-coast states during WW2 was ethnic cleansing. But it certainly wasn't genocide, because no one was killed (that I know of).

I suppose you could call that "forced removal" but that term leaves out the fact that a certain ethnic group is being targeted.