First, women are just 20% of all AIDS victims. Mind not blown, Mr. Un-PC Dude.
Second, that shows a fair degree of missing the point of fiction. Sure, in real life, where everything happens according to cold statistics, promiscuous women will tend to get more AIDS than non-promiscuous women and non-promiscuous heterosexual men. Granted.
But this is fiction, a work of art which has an audience and a message, where everything happens because the author wants to. Even if you don't want to, even if you're scared shitless of communicating a Message, you are in fact, as an author, putting a point across. It might not be a message that you as an author subscribe to, but the work is there, and the point is made; and you're just a bad author. And people are naturally adept at finding the core message of works of fiction; we as a species seem to like narrative a lot.
We look at those Nazis melting at the end of the first Indiana Jones movie, and we instinctively get it: they were punished because of their arrogance and evilness (in this case Naziness). Even one Nazi got stigmata, as a symbolical punishment and marker of his inherent badness, that is, Naziness. It's all narrative, and a message gets made, namely that being Nazi is kind of a bad deal. Take Elon Musk, he's the hero in a narrative that pits the Startupy Original Innovators (good) against Sclerotic Big Corporations like Boeing (bad); and it's hinted that badness will be punished at the end and good will prevail, as it is defined in the (narrow, a bit unfair) context of that narrative. A very common and crude narrative structure; and very powerful, by the way.
So, this guy watches Forrest Gump in a culture that tends to shame women that have casual sex, and sees that it just so happens a woman that has casual sex then has (is punished with, the mind readily answers, since it's just too much of a coincidence...) AIDS, because this author just decided for it to happen. And this guy then infers the writer has made a moralizing tale where sluts get AIDS. Now, maybe this author was just clueless and didn't think through the implications of his, or her, decisions; but I wouldn't blame the GP for looking at Forrest Gump that way.