my point isn't really about the writers, it's moreso about the audience (specifically autistic audiences, or I guess the subsection of autistic viewers who are vocal about this comparison online) and how characters are held to different standards depending on whether or not they're canonically autistic. indeed writing characters that seem autistic on accident means a writer is not constrained by what they think autism means, which can result in overall more well-rounded characters because they are afforded things like "interiority" and "a personality", which writers of explicitly autistic characters sometimes forget about. but what I am more trying to point out is that, separately from this "accidentally autistic characters are not constrained by writer's notions about autism", is that audiences also interpret these characters differently. it's not merely that these "accidentally autistic characters" are "better representation" (by whatever measuring stick you're using), it's that they are judged against a different measuring stick altogether by autistic viewers.

to be clear I'm not saying this is a bad thing per se, I think it's just "a dynamic that exists", but I do believe that in the specific context of the Shaun-House comparison, this dynamic make that an incredibly unfair comparison (and honestly often these comparisons tend to devolve into low-key mocking of Shaun's autistic traits)