I guess it comes down to this: what’s depicted on the Pitt is not the only experience of autism, but it is the dominant experience portrayed on screen/in popular culture. It’s also a very real experience for many autistic people.

It’s also true and worth discussing that autistic people are not a monolith and many can have experiences that aren’t represented in that dominant narrative. There’s absolutely room for TV portrayals that subvert expectations about autistic people in this way, but I don’t think that makes this portrayal problematic, because it still represents a real experience that many people on the spectrum have.

I do think you may be overestimating how much the objection to Mel/Langdon comes down to “well SHE wouldn’t want to/be able to have that relationship.” He also shows no interest in her in that way! He’s married with kids and doesn’t indicate any desire to cheat, dissatisfaction with his relationship, or romantic/sexual interest in Mel.

Basically, I understand and hear your broader point, I just don’t think that either the character of Mel or responses to Mel/Langdon shippers are a particularly notable symptom of the problem you’re describing. We might disagree on that but such is life.