I do agree a lot more study is needed.
But I would add that I live very near a large Amish community. They don’t have TV. I know lots of them. I have never heard of an Amish kid with autism. I am sure there are some but not nearly at the rate as the general population.
Up until a certian age our sensory signals are still developing. Overstimulation could very well cause damage.
And I’ve heard people make the same argument about the Amish and vaccines.
The Amish are a very homogeneous group (genetically). That plays into the autism factor much more than television or vaccines.
That said, I do agree that sensory skills and brain development under the age of three is crucial. It is why we do try very hard to limit television for our daughter and we choose to delay many of her vaccines. Not because we think they cause autism, but because they can interfere with brain development.