A 'Mitch' is a variety of human being, that is both extremist, and
non-accepting of other people's beliefs.
The standard Mitch is generally Christian to the extreme, and unable to take in another person's beliefs. If someone was being a Mitch, he or she would be behaving in a way that shows he or she knows
nothing about any other belief other than their own, and that it gives them the
right to defend it at all costs. If someone were 'pulling a Mitch', they would be behaving in a way that shows they are extremely closed-minded, while continually telling themself that they're actually incredibly open-minded, when it is simply not the
case.
Extremist, and
one-sided.