I'm sorry, did someone really think that a high school extra curricular was going to act as some kind of deep and wisened meditation for teens on rhetoric?
More than anything else, debate forces you to think quick on your feet - really, /really/ quick. Tantamount to an e-sport, but WAY more open ended, since the aff and neg can run just about anything under the sun, or even go meta (which seems more common since the early 90's when I debated).
Yes debate is a terrible model for useful rhetoric. It's also a hellishly fun boxing match for brains/mouths.