Agreed. But some people seem to think that the low IQ kids don't need or deserve education. They do. But it should not come at the expense of normal IQ or high IQ kids. Unfortunately, it does because the only way special ed kids can get the best education is to be mainstreamed with a special aide to help them. I know because my brother's oldest two kids are high IQ kids and his youngest has Down Syndrome. Mainstreamed - but left back two years in a row at his parents' request - he reads and does arithmetic better than most of the kids in his first grade class. Next year they will move him to second grade so he can get his reading up to par too. He may stay in second grade for a couple of years till his speech ability catches up to everyone else's. By then, he will know how to read, write and do math - in a regular class.
My youngest brother has down syndrome and he attends a school just for kids with disabilities. They are grouped by ability, every teacher is a special needs' teacher, they have all the help they want. It works in a way mainstreaming just can't. He's very fortunate that such a school exists not far from my parents' house.
The problem with mainstreaming is even if you hold the kid back until he's mastered the work, at some point you're going to have a 16 year old in fourth grade. That's just asking for trouble. Not to mention the other kids in the class who are probably getting a very negative view of people with disabilities as "that big slow kid who wastes all our time".
While I think mainstreaming is better than sticking disabled kids in an institution to die, it's not at all ideal. A school designed to work only with special needs kids can concentrate the resources they need.
I think we need to look at how IDEA came about. Prior to IDEA, "special ed" kids weren't being taught badly, they weren't being taught AT ALL. When the laws changed, no one knew what to do with them. It has taken time to figure out how to best help them. Special ed teachers, in my experience, are generally very good. THEY are the ones we all go to!
Kids aren't being mainstreamed because special ed teachers aren't doing a good job, but because parents want their kids treated as much like everyone else as possible.
I'll bet many special ed teachers would like to have complete control over "their" students because the most often complaint I hear is that the regular teachers are resistant to the special ed teacher's advice and inconsistent with behavior programs.
My 3rd grade son has learning disabilities. Personally, I'd much rather have him removed to a smaller, quieter room and getting one on one attention. Most times what happens is the sp. ed kids are all placed at one table, the classrooms are still noisy and distracting and the sp. ed teacher is trying to help 4-5 kids at the same time.