I'm working on a theory. When I miss a social que or don't read somebody's visible emotions, it's not because I didn't see the sad face or missed some context. Usually I'm seeing a whole bunch of conflicting emotional cues or social context clues but learned at a young age that I can't just make an assumption based on one of those. Some times people lie, some times they say one thing but mean another, some social rules compel certain contrary behaviors on top of all that. And also I have to be aware that I may have actually missed something so the info I'm seeing isn't always enough to make an assumption on either.
I don't think we're the ones who can't read emotions, I think we are reading more things all at once and can't select 1 possibility to act upon when presented with a social dilemma like reading an emotion. Does that resonate with anyone else?