It took me less than minute to find a study saying that 1 of 271 Amish kids had autism..
This study you are citing is NOT concerned with idiopathic Autism or vaccination correlation. It did not specify relationship to vaccinations. Vaccinated children were not excluded from this study. The research was studying populations which are not ethnically diverse and the incidence of autism related disorders (genetic and idiopathic being lumped together). These quotes from may help you understand the issue more fully...
“Strauss said the clinic treats “syndromic autism”, where autism as part of a more complicated clinical spectrum that can include mental retardation, chromosomal abnormalities, unusual facial features, and short stature, as well as Fragile X syndrome. “We see quite a few Amish children with Fragile X,” he said.”
(These things being seen more frequently in the Amish, who have a high prevalence of genetic risk factors and are NOT included in the symptoms of vaccination- related autism behaviors.)
Strauss says he doesn’t see “idiopathic autism” at the clinic, which he defines as children with average or above average IQs who display autistic behavior. “My personal experience is we don’t see a lot of Amish children with idiopathic autism. It doesn’t mean they don’t exist, only that we aren’t seeing them at the clinic.”