[nine_k]

I personally suppose that seeing someone as an idiot because of difference in opinions is more debilitating than having an arbitrarily wrong opinion.

World is not black and white, and has never been.

[untog]

I personally suppose that seeing someone as an idiot because of difference in opinions

Are there any other reasons?

[coldtea]

Yes, the canonical reason is because he has a reduced mental capacity, something that can (possibly) even be measured in standardized tests.

Not because he has a different stance on moral issue X.

[Confusion]

Funny you should say that, as you are interpreting the comment you are responding to in a decidedly black-and-white fashion. When someone says someone else 'is an idiot', that usually means: "he's an idiot concerning this issue, which is actually surprising, since he mostly holds sensible and defensible opinions". It's not either black-'someone is an idiot in every aspect' or white-'someone is awesome in every aspect'.

[nine_k]

I'm sorry: I take words by their direct meanings, as long as the resulting sentence makes sense.

I understand that various (probably arbitrary) interpretations can be attached to a sentence by assuming metaphorical, implied, contextually altered, ironic, humorous, etc meanings of words. I still prefer to assume as little as possible: pluralitas non est ponenda sine necessitas.