oh dear, because there is so much good research going on in the field of autism. When there is nothing available, I can see people trying some alternative junk. I know my husbands cousin turned to woo when her bone cancer was diagnosed (and she was asked if she even wanted to do chemo, since there was no hope). Heck, I even bought her some crystals (pre JREF days, I didn't believe, but she had asked for help from everyone...).
But when there are good treatments available! And, a lot of this treatment for autism is time sensitive!!! You can't think, "well, the exorcism didn't work, he's 14 now, let's try to school with the early intervention!!!"