Am I imagining a 'trend' of excusing misogymy with a lay diagnosis of ASD?

It does seem to be the new "in thing," doesn't it?

I've noticed that it also goes hand in hand with an OP expecting their OH to read their mind and know exactly what they are thinking and what they need.

Personally, I think in most of those situations, the OP simply needs to be more mature and actually communicate properly with their OH. I am tired of seeing the wave of armchair diagnoses.

I suspect the way that autism has been defined and diagnosed is itself sexist. A poster who has an ASD posted some interesting stuff about how the underlying traits of people with anorexia nervosa is so similar to ASD that a number of researchers are now considering looking at autism differently in terms of how it manifests itself.

That has led to a trial in different way of treating anorexia that has been successful. As most anorexics are female, revising a diagnosis of autism in a way that included many (but presumably not all of them) people with anorexia could change the whole autism = extreme male brain idea and help a lot of women, as most anorexics are women.

I don't know, I have never heard this. But look at this article about positive Aspberger traits: jennifercopley.suite101.com/positive-traits-of-aspergers-syndrome-a64523
One is "Aspies are very accepting of the quirks and idiosyncrasies of others. Most don?t discriminate against anyone based on race, gender, age, or any other surface criteria, but instead judge people based on their behaviour. They don't usually recognize hierarchies, and so are unlikely to accord someone superior status simply because that person is wealthy or has attained a high position in an organization."
Of course, everyone is different and some ASD guys might be sexist jerks. It's not a symptom of ASD though, it really stupid to blame sexism on such things.