> Many others feel the Pope is not Catholic (which of course is impossible by definition).

interestingly enough this could make sense (although quite likely not in the case of Breitbart commenters).

For example, the eastern orthodox church, like the roman church, defines itself as "One, Holy, Catholic and Apostolic", so an eastern orthodox christian may well refer to itself as "catholic" while denying the Pope is.

This seem to be the reason that in some places people often refer to "catholic" as "roman catholic".