The fact is that a person who is very much hated by homosexuals, because he figured the younger mortality rates of men who have sex with men as opposed to normal people, said the men having sex with men is preferable to the term homosexual because homosexual and gay implies an identity where men having sex with men describes a series of acts (many of them entirely nauseating). If they are called homosexuals, the men having sex with men can say they are gay men and they are being persecuted for their identity (say... such as black people). The people who practice the deadly perversion will say they are persecuted by bigots against their identity -- just as black people are. How the cultural communists happened upon the more correct terminology for these practitioners of a deadly perversion is unknown to me, however.
"Men having sex with men," as in the article posted in this thread, quickly morphs into "MSM." MSM has been used for at least a decade to stand for "mainstream media." So I'd prefer not to use the same abbreviation for two obnoxious, though different, groups.