Damny, I'm guessing there are people who actually think that way. There are good reasons as to why special ed kids should attend regular schools. One of the biggest reasons is it shows kids that there can be extreme differences in ability and mobility between people and that everyone is different. It helps the mentally challenged children grow and learn. Their parents need to be able to work (though in my city a lot of the parents of kids with fetal alcohol syndrome don't work) and i t costs more to have different schools for different people.
There are negatives about adding disabled children to schools, like adapting the school to meet their needs, hiring staff to take care of them. The disabled kids take up space for other capable students, some of them disrupt the class and some other things. I think the benefit outweighs the cons and helping kids grow is more important especially when it comes to relating to others, understanding and sympathizing as we can all be in the same bad situations.