"In the post hoc analyses, an increase in sexual inactivity and having no sexual partners among men was observed in most sociodemographic subgroups but not among gay or bisexual participants..."
[1] https://jamanetwork.com/journals/jamanetworkopen/fullarticle...
Medical advancements such as the availability of PrEP have been a boon to the gay community, and it's paired with frequent STD testing.
Gay men are exposed to the same environmental hazards, and also have smartphones/social media, so I'm not convinced that's what been slowing down their straight counterparts.