Uh, because the people bringing and selling drugs in school zones are mostly teenagers who go to those schools? Yeah, lock the fuckers up, keep those private prisons full.
C'mon man, got to keep the drug pipeline running for the rich bastards that never have to suffer for it one way or another. Though now I'm half wondering how much that line of reasoning might actually have been involved. Oklahoma happen to have one of its major drug trades be one of the sorts preferred by better off folks?
'Course, as a broader thing goes, I'd probably argue pretty cheerfully against mandatory sentencing for
anything, at the absolute least so far as felony classification and incarceration time goes. Shit seems to cause more problems than it solves pretty consistently, and often enough by a pretty sizeable margin. Be willing to lay good odds we'd be better off just without the damned stuff.