I don't know what your experience was like in undergrad, but at the state school I went to, the 100-level "intro to this major" type courses were actually quite

I don't know what your experience was like in undergrad, but at the state school I went to, the 100-level "intro to this major" type courses were actually quite challenging. none of the individual pieces were that complicated, but the breadth of material and pace were simply too much for most high school students, let alone middle school. I also dispute your claim that 100-level courses should just be assigned to grad students. of course any grad student should have a firm grasp of the intro material, but intro courses aren't _just_ about learning tools and building blocks for understanding advanced material. they are a department's first opportunity to get students excited about their discipline and get them to start thinking about how all the little pieces fit into a larger perspective. simply throwing grad students at these important courses is a great disservice, imo. to be fair, the current practice of shoving 200+ students into a huge lecture hall is not much better, no matter how good the instructor.