I’m always over cautious about younger blokes because (a) I’m conscious of the reasons for consent laws - to protect them from their own impulses from exploitation by older, more experienced people who oftentimes have a real power imbalance; (b) we’re talking specifically about HIV and AIDS here - I’m the first person to agree that I find the risk-taking adds sexually hugely exciting - and the long term health impact of retro-virals for those commencing in them with expected lifespans of another 65-70 years at least can’t yet be known; (c) while I have known many who I believed had sufficient mental maturity at a young age to make their own decisions about sex and their sexual activities, I’ve also known well others for whom 18 probably wasn’t old enough; and (d) I’ve had two friends who were pozzed at 22 and 18 - carelessly by a mate and deliberately stealthed by his then boyfriend - at which time, the “boyfriend” ignored the devastation in front of him, celebrated, including bragging about his “success” in front of him, then ending the relationship and marching off because it’s only purpose (for him) had been served.
All this took place while others, including me, were enroute to where he sat, bawling in the gutter, utterly shattered by what he’d just learned.
If you’ve ever had to try and help someone just go on from such utter betrayal, you’re likely going to err on the side of caution too.
And, yes, I do often tell younger men that, while I respect their decision, I’ll generally discourage them and certainly won’t abet them in that course...and, yes, I’m fully aware of my own hypocrisy given that I now regret not accepting my own attraction to sex with men as well as women in my early teens. With the full benefit of hindsight, I’ve no doubt that fighting my strong desire for other men until my mid-20s is now a complete waste, especially given how “fulsomely” I pursued those desires once I experienced them.