My situation was similar. Went to public magnet schools from 6th grade on. I never felt like I was being "groomed" for anything, despite the fact that the magnet program I was in was geared towards science and engineering. If you didn't want to take the fancy advanced math classes, then you could probably have gotten though the program without doing so. Though, if that's not what you were interested in, then why are you going to a science and engineering focused school?

As far as keeping the unwashed masses down, it's worth noting that both magnet programs were "school within a school" type deals. Anybody from the "greater" school who wanted to take a magnet class could do so, as long as their grades were up to snuff. It so happened that the campuses that housed the magnet programs were poor inner city schools with serious academic issues, so the regular kids rarely took advantage of the opportunity.

Also, I'd dispute the claim that its to the advantage of corporate America for the public school system to churn out mindless drones who can't think for themselves. For any type of employment *other* than menial work, you generally want someone who is sharp, can problem solve, can think for themselves, can self-educate, etc. It's just a fact that not everybody is...well, all that smart.