Having grown up strictly Catholic I can tell you it’s because they view the world extremely binary black and white. Either you’re a Christian, or you’re “led astray by Satan’s lies”, so literally everything else is Satanism.
To a Catholic even a Protestant could be considered a Satanist.
To be fair a lot of protestants don’t believe Roman Catholics are Christian either because if the overt idolatry and the whole fact that the state that supposedly killed Jesus also formed the Roman Catholic Church.
Having grown up strictly Catholic I can tell you it’s because they view the world extremely binary black and white. Either you’re a Christian, or you’re “led astray by Satan’s lies”, so literally everything else is Satanism.
To a Catholic even a Protestant could be considered a Satanist.
To be fair a lot of protestants don’t believe Roman Catholics are Christian either because if the overt idolatry and the whole fact that the state that supposedly killed Jesus also formed the Roman Catholic Church.