Romeo and Juliet are not idiots, they are clearly the most sensible persons in the play. And it is anachronisic to call them teenagers, since the idea of “teenage” as a stage between childhood and adulthood is a 20th century innovation. In the universe of the play, they are adults and of marrying age.
Apparently some teachers try to teach the play as a warning against young love - probably because they are afraid of students emulating the sex and suicide. But if you actually read the play, it is entirely on the side of the young lovers and condemns the parents and society. Radical, even today!