It would be considered “ethnic cleansing” if whites were immigrating in overwhelming numbers to any black, brown, or yellow nation and race-replacing the inhabitants. The UN would be calling for measures to stop it. Only in white nations is race-replacement—”ethnic cleansing”—acceptable, even desirable.
Which is why this can't go on unchallenged anymore. The world has no deficiency of anti-white sentiment, and this should be no more acceptable than any other kind of bigotry.