Again, I think the important point is that when you choose to have sex with a drunk random you pick up at a taxi rank you are leaving yourself open to all sorts of risks. The person may be underage, or have an STI, or be married, or be a serial killer.
So if a woman had a ONS with a guy who turned out to be a serial killer and murdered her, would you say "oh well, she knew she was taking a risk by sleeping with a random she picked up at a taxi rank, it's her own fault really"??
Yes, of course he opened himself up to all sorts of risks just like anyone does when they have casual sex with a stranger. Does that mean everyone who has casual sex basically deserves any shitty situation they find themselves in? Of course life isn't fair but that doesn't mean the law shouldn't try to be fair. And it doesn't mean we can't feel sympathy for someone who ends up in a bad situation after taking such a risk. Wouldn't you feel some sympathy for someone who contracted an STI after a ONS, for example? Or would you just say they had it coming because of their risky choice?
And yes, we require ID to be shown when buying alcohol. But the difference is that we don't throw people in jail if they fail to check ID - the most they can expect is a fine.
I really can't believe a couple of people are condemning this guy in the same breath as admitting they almost did exactly the same thing themselves 