Do Catholics need to believe that the Pope is infallible to enter heaven?
Do Protestants need to believe either one to enter heaven?
I would say that someone is a Catholic and doesn't believe those things, he needs to get clear in his own head why he's a Catholic.
And if someone isn't a Catholic and cares enough about it to take a thread about an apostate Muslim congresscritter and turn it into a donnybrook with Catholics, he should REALLY study his opposition rather than confine himself to what those on his side say about us.
I think thoughtlessness is a vice and negligent ignorance can be a sin. Leaving aside "getting into heaven" I would think people would want to avoid vices and sins out of their love of God and His goodness.