The No True Christian Fallacy

[Neo-Scholastic]

...may not act as a Christian ought to, but that does not make them not Christian...

That's one of the dilemma's of orthodox Christianity is that you don't need to be a very good Christian to enjoy your "Get-Out-of-Hell-Free" card. People get sorted into two groups: saved and not-saved. It's a pass-fail test. Most other religions, and some Christian denominations like Swedenborgians (that's me), make allowances for how well you followed the specific practices and teachings of the faith.