Autistic person here:

Yep, you got it.

Its complex consistent pattern creation, its fixation on details/components.

And you're right to point out how its much more complicated than 'oh they do this thing so they must be autistic'.

But I will push back slightly against the 'ground up' thinking framework.

Its not so much that it needs to be details -> small concepts -> big concepts... its that the framework needs to be consistent and well defined, without exceptions or vaugeries.

Autistic people can totally understand something, starting from a big picture perspective, if you actually explain all the mechanistic concepts, from the top down to the bottom.

What neurotypicals often do is just forget to explain edges cases, ignore contradictions that they don't even realize are present, because they don't evaluate the concepts for potential contradictions that thoroughly.

That's the strength of the neurotypical thinking mode: its faster, less mentally taxing, less stressful. Less rigorous and accurate, but its faster, and works in most common cases. A 'good enough' heuristic.

Thats why autistic people often struggle with socializing: They're getting a whole bunch of different feedback from different people with different personalities who have different uses and meanings for the same words, who have different opinions about what is or is not appropriate in what kind of situation/context, who have different kinds of facial expressions, body language, tone shifts, etc.

This is very hard to consolidate into a consistent, stable, detailed, non-contradicting framework for how to socialize, because everyone is actually 'playing' by slightly different rules... but neurotypicals do not realize the extent to which that is true.

What is much easier to do, for an autist, is to model a single person's 'social rules', or a small group of similar people's 'social rules'.

We call that 'masking'.

Then you just switch masks, switch social etiquette rules, when you are around a different group.

Its easier to have a few, smaller, consistent models of socializing, than it is to try and ... consolidate them into a sort of grand, unified, totally consistent socializing framework.

... Because when you try to do that, you realize more and more contradictions.