You’ve got my reasoning correct (the questions are too pointed and susceptible to confirmation bias), but I still disagree with you in that these tools are designed to tell most people they have autism even if minor.

Some egregious questions that always pop up are “do sounds annoy you”(paraphrasing) and “do you find that social situations can be overwhelming”, and an especially bad one: “do you get fixated on specific topics or collections of items”. Most people will say yes, because they have hobbies and think they are “quirky” but this is really referring to obsession with stuff to the point it degrades your life.

Because of that susceptibility and the probability that a lot of people taking these tests already subconsciously think they might be autistic leads to basically everyone coming away from those tools with “signs of autism” at the least.

Then we end up in the current society where it’s apparently cool to be autistic and not some life ruining disease it is.