Some people do not consider Catholics to be Christians. Oh, boy, what nasty things I could say about that opinion!
I don't consider all Catholics Christian, any more than I do all protestants. Do you think the Mafia are Christian? Most of them are good Catholics but I would never consider them Christian (just one example). I know many good and devout Catholics. I also know some who are just church goers and then go out and do whatever they darn please. They don't have a clue as to what Jesus demands of them (righteousness, holiness, and all that good stuff).