Okay, and I believe they are in for a rude awakening when they face Judgement. That, however, doesn't change the basic nature of Christianity, which is that Christ paid the penalty for ALL sin if we only accept it. There are apostate Jews, do they invalidate Judaism?
I will cite again how we expect someone to behave when they fall in love. If their behavior doesn't change at all, we have to ask, are they really in love or are they just parroting some words designed to make people think they are in love? Does doing nice things for someone and saying nice things about them make you in love with them, or do you do those things because you fall in love with them? So it is with Christianity. Doing good works doesn't make you a Christian, but you should naturally be doing good works as evidence that you are in fact a Christian.
IOW, the works themselves don't do anything to save you, they are just the evidence that you are saved.