The comments about the safe sex campaigners are partly the answer to the questions upthread about promiscuity.
In the late 70s and early 80s public health professionals were seriously concerned about the spread of STDs in parts of the gay community, particularly at that point Hep B. But unfortunately (not too dissimilar to mask wearing I guess) the whole issue was politicised. After the legalisation of homesexuality in many countries, any attempt to restrict the hedonistic promiscuous lifestyle was seen as homophobic or repressive. There were voices all along saying that unprotected sex with many partners was a very bad idea but they were ignored or shouted down.
Even after AIDS emerged, this was still an issue. When San Francisco closed the famous bath houses, there remained opposition from within the gay community, even with the evidence that they were acting as infection vectors and people were dying.
That line of dialogue was a nod to all that. How politics interfere with science.
I think there is a generation of people now in their 50s/40s who were very marked by AIDS and the fear of it, who see safe sex as hugely important. Don’t Die Of Ignorance burned in our brains here in the UK. But people younger who have grown up in an era of effective treatment for HIV don’t have that so much and STDs are rising again, as has already been stated.
I do see some of the parallels between HIV and Covid but I do think medical staff have come a long way, even if the population hasn’t. Isolating Covid patients was about method of transmission more than anything else. We knew HIV wasn’t airborne a long time before people dying with AIDS were treated better. And there was very definitely worse treatment of gay men and drug users, who had brought HIV on themselves, rather than the ‘innocent victims’ who contracted it via blood transfusions. A lot of othering went on.