Exactly which multiculturalist do you think are "at ease" with that behavior?

About as many as there are environmentalists who are "at ease" with the mercury content of compact fluorescent bulbs, while campaigning to abolish incandescents. Female genital mutilation is a cultural practice, but instead of saying that this cultural practice is wrong and should be stopped, which a multiculturalist cannot do, some of them say that "there are cultural and political aspects to the practice's continuation that make opposition to it a complex issue", or that "the ritual of FGM has been the primary context in some communities in which the women come together", or that colonial attempts at eradication constitute "interference with women's decisions about their own rituals", or that "its apparent victims were in fact its central actors". Quotes from Wikipedia.

A multiculturalist could take a different tack and argue that FGM is not a cultural practice, making it permissible to oppose. However, since it is a cultural practice, and is clearly understood and explicitly stated by those who practice it to be a cultural practice, that isn't so easy to maintain. But I doubt impossible; the insanity is not peculiar to philosophers and theologians, but is bred whenever one is obliged to cling to both sides of a contradiction.