I would wager that a far larger number of those Catholics know that the Church teaches that Jesus lived without sin and yet they don't believe it. In the same way that the Proddies know that their churches teach that avenging oneself is wrong but they do something different. So, doctrine is not the biggest problem there in my estimation.
I disagree. Wrong doctrine is a big problem.
There's error. Which is abundant. And damnable error. Which is not nearly as abundant, at least in my estimation.
I would qualify that with my own quote.
The internet has done for heresy what the printing press did for Protestantism.
-the808bass
Of course, as a Catholic, I suppose I would have to say, "The Internet has done for heresy what the printing press did for heresy." :-0
That's the bad news. The good news is that the Internet has drastically lowered the barrier to entry into the discussion, so that, while there's a lot of dross, there is considerable gold as well.