Well, communion/passover wine is alcohol too, and you're allowed to have it in public legally, sort of/depending, even if you're a minor, though I doubt that's being drunk for recreational purposes in most cases.
He could have been making a sort of false assumption, like "I'd suggest beer, I mean, on the off chance you have a taste for something else, which would imply you've had alcohol before, which is unlikely..." just like that one lemony narrator who makes assumptions about his audience. Like, "This book you are reading, or are having read to you by someone for some odd reason, because this book is most certainly for people above the average age of literacy in the states and if you have to have this read to you, than you probably should close this book before I say something innappropriate or some shit." Does the author honestly believe his readers are children hearing this bedtime-story-style? Probably not, but y'know, the joke is there, and you're also factually covered in the case where your offhanded assumption is actually true.
