I don't think it's possible in this case. And, yes, I think it is a sufficient reason that such comments shouldn't be made. Not because it's exclusionary (although discrimination is an awful thing, I don't think homosexual people would mind being excluded from the implications of the premise we're discussing), but because it shows how wrong the comment is. The implication is that specifically heterosexual persons have the sex-friendship issue, or if not, then all humans have this issue, in which case the "men and women" part has to be thrown out.

Is there any evidence that friendship, sexual and romantic relations work differently among homosexual people? And to such an extent that the negative tension between sex and friendship exists only with heterosexual people? I don't know of any. Has anyone ever made a comment: "Gay men can't be friends because sex always gets in the way." or "Lesbians can't be friends because sex always gets in the way."?

I'm not implying there's homophobia in this kind of thinking, just very bad, shallow "analysis" of interpersonal relationships (of the kind you tend to get from "women magazines" and "men magazines", no surprise there) and, in some cases, a lot of rationalisation by people who only want infantile sexual relations from persons of desirable sex and don't even try to make friends, although they try to fake it to get sex (i.e. by people for whom friendship was never actually a motivating option).