For the same reason I already stated...If you cannot be honest about the little details tell me why should you be trusted with the big ones? There is a LOT of stuff in Roman Catholicism that others are expected to just accept what has been guessed at or imagined and is far from a "guess as accurate as any other". We don't base our eternal destiny on the things that can be only guessed at. The stuff that can be proved from Holy Scripture, I have no problem with and I DO accept by faith because GOD said it. When the RCC holds to those same doctrines, we can agree. Where they swerve off into guesswork, wishful thinking or assumptions - especially when these are contrary to Scripture - then we should trust in Scripture rather than the proclamations of fallible men - no matter how high up they claim to be.
the Catholic Church wrote scripture so they officially NEVER declare anything contrary to it. The proclamations she makes are not made by fallible men, but by an infallible hierarchy....guaranteed so by Christ Himself....I'll buy that!