Urban dictionary has an interesting definition that expands a tiny bit on how you defined it:
http://www.urbandictionary.com/define.php?term=metrocon
Metrocons typically derive their worldview from some sort of intellectual reasoning, as opposed to soaking up the worldview from base emotions, reflexes and socializing with like-minded people, like hardcore people of other political orientations typically do. This makes them typically much more tolerant than other conservatives are, so metrocons are often viewed by hardcore conservatives as 'fake' or 'meek' or not genuine, somewhat similar to RINOs (Republican In Name Only), with an obvious difference, though: RINOs can be rural or metropolitan.
I love how pretentious that definition is....