This is a sensitive subject, but that's partly changed thanks to drugs like Truvada and PrEP.

You can now have sex with someone who has HIV and still not contract it. People are having more unprotected sex, safe in the knowledge that they're on PrEP and they basically can't contract HIV anymore. Hell, AFAIK you can even take a large dose of PrEP or Truvada AFTER you've had risky sex. This is great news. Not having safe sex isn't. It's a problem in the gay community.

Important caveat: apparently people are also getting tested more often exactly because HIV is now far more treatable or preventable, which means doctors are diagnosing cases of syphilis which would otherwise have gone undetected (syphillis can often be asymptomatic until it starts causing serious damage):

https://www.cbsnews.com/news/syphilis-rates-gay-bisexual-men/