[dEnigma]

But we can blame a person with perfectly functioning legs if they pretend to have a limp and e.g. cause a congestion in a subway station. The line should be between "having trouble walking" and "being able to walk just fine", not somewhere on the spectrum between a limp and a missing leg. Same with intelligence, there should be a line above which a person should be able to act normally (as opposed to stupidly). I'm not trying to make a distinction according to the severity of mental disabilities, but between having one and not having one; between purposefully or negligently acting "stupid", and having no other choice. Which, again, can never be done without error; so some people will be unfairly blamed or the other way around. But the alternative is to just accept any kind of stupid behaviour, even from people who have the option to behave better.

>Why do we blame dumb people for their dumbness, but only if they're not too dumb?

Adding to what I wrote above: Ideally we shouldn't blame "dumb" people at all, just relatively smart, or normal, people who act dumb. I will agree though that we (myself included) often do exactly what you described, blaming dumb people, which is wrong in my opinion. "Dumb people" should be understood, educated and/or supported, not blamed.

[mikeash]

"act normally (as opposed to stupidly)"

This might be the root of our disagreement. I don't see these as being in opposition at all. Stupidity is normal.