The original rule bars 'a man who has had sex with a man' - X - and then any women who've had sex with X. It's a logical phrasing but unfortunately X maps exactly onto "gay man", so it feels like gay men are being specifically targeted. The rephrasing mollifies that sense of targeting without, as far as I can tell, changing the included or excluded people.

The original phrase is even-handed, however. If you overspecified an even-handed rule and said "1) You cannot donate if you're a man who has had sex with a man who has had sex with a man, and 2) you cannot donate if you're a woman who has had sex with a man who has had sex with a man" - ie, prevent "man who has had sex with a man" from coming into sexual contact with any donor - you could reduce 1) down to "man who has had sex with a man" (it logically implies three, four, and so on iterations). This, therefore, reduces down to the actual rule they have in place.