This is not only why we have Indifferentism spreading among the pews and the clergy, but even scientists who claim to seek the truth in the natural order are increasingly wandering into mythmaking with ideas like multiverses (which are designed to explain away fine tuning while not acknowledging God's hand). To see the later, look up the Science Fictions series by Denyse O'Leary.
The answer is to speak the truth in charity, which also means being sparing with the irony (a matter in which I am, I must admit, the foremost of sinners).
The first examples comes from China, where a man returned to a Daoist temple to give thanks to an idol for letting him have a child. Why did he not go to have a mass celebrated?
Now for something closer to home, how about the number of people, even on CM, that are practicing yoga. Many are ignorant of this, but yoga is a practice of the Hindu religion, and is considered inseparable from it by Hindus. Just recently there was a hindu leader that told Christians that they should not perform yoga for that very reason.
Sad to think that leaders of pagan religions are more soliticous for the preservation of their faith than lay Catholics or even the clergy.