The short of it is that people on the spectrum focus on the details, and ignore 'extraneous' information. The typical emotional appeals--such as the choice of certain fonts, colors, graphics, emotional language, etc., is going to be largely ignored by people on the spectrum, while they focus on the details that are directly relevant to the use of the product.
I've noted this tendency in myself (and yes, I"m on the spectrum).
Obvs. that doesn't mean that all advertising falls flat, just that the kinds of emotional appeals that are more typical in advertisement are going to be less effective.
Is it really just autistic folks? I see marketing material all the time that frustrates because they tell me nothing about the product I'm trying to research.
Like a phone product page saying things like "our camera helps you capture the moments that matter". Well, duh, I know what a camera does and everyone has a camera, but is there anything particularly nice about your camera? Marketing material wastes so much material on uselessly vague stuff. Extra madness when their web design hijacks scrolling to pause my scrolling to change it to advancing some animation..
It's not just autistic people, no, but autistic people appear to be better at filtering than neurotypical people.
Imagine two cameras in boxes. One is in a white box with black text that lists camera specs. The other is a brightly colored box that has examples of the photos taken with that came, along with a more sparsely populated list of specs. Which are you more likely to buy? Most people--not all, but most--are going to gravitate towards the more appealing packaging unless there are pretty gross differences in specifications that make it less desirable. People might be willing to pay somewhat more for the appealing packaging, as long as the specs appear roughly similar. Autistic people are supposedly better at filtering that kind of information out.