Believe it or not, I have met many girls and two guys who are just like the uke. Its pretty much because they were sheltered by their parents. And were more focused on school than dating.
I believe you though I can't say I have ever met anyone like that. And I have traveled to some fairly religiously conservative countries. Even in those places where they were given a strict religious upbringing, I found older teens (16-17 yr olds) sometimes woefully ignorant of the most basic facts of life, but somehow by the early 20's they seemed to have learned quite a bit. Even about things such as homosexuality, and anything else, not that it meant they approved of it.
Once again we have an unbelievably innocent, naive, not to mention ignorant uke. Hard to believe this guy is supposed be 22. He reminds me more of a shoujo MC (the never been kissed virgin 20+). So while I'm enjoying this, I admit I would probably have liked it a whole lot more if it had avoided the yaoi trope, and made him just a little more his age and aware, and less the cute and sweet dumb bunny.