If that was statistically significantly true, Sweden would be autism central. We have since sometime in the 70's been giving our children milk with every meal.
When I was growing up through the 90s in America this was a pretty normal thing too. I drank a lot of milk as a child. Like I have a lot of anxiety now but other than liking trains I don't really seem that autistic.
We had a huge campaign for kids to drink milk in the 80s and 90s. There was the 'Milk: It does the body good' ads, which became a pop culture sensation, and then they did the "where's your mustache" ads where they had all kinds of supermodels and other celebrities drinking milk and showing a milk mustache.
Of course, the dairy industry is hugely subsidized in the U.S.
Basically, everyone in the U.S. born between about 1975 and 2005 should be autistic.