I don’t think the problem here is people aren’t aware that venereal disease is a possible result of unprotected sex. You have provided just as little evidence for your assertion to the contrary.
My hunch is that people are probably generally unaware of the recent rise in syphilis cases, would do well to be more informed, and with proliferation of the message some general adjustment of behavior in society is to be expected
My hunch is that that isn’t true because people on the story are shrugging off multiple infections.
Again anecdotal evidence. Just because some people shrug off multiple infections does not mean awareness has no influence.
And your "hunches" are rigorous? If you are going to demand rigor of your interlocutors I would say you have an obligation to demonstrate it yourself.