Most parodies must have an element of "funny because it's true", in order to be recognized as parodies and also to succeed as parodies.
Since the Catholic Church doesn't depict its existing saints in the manner described, it's kind of a stretch to make a joke about how they would suddenly do something totally different, saint-wise.
The other implications are equally ungrounded in reality.
The "Religious Right" is a term used to describe a protestant faction. The entire fantasy falls apart in the first sentence, where we are asked to imagine protestants and papists joining forces to form some kind of political Voltron--easily the most hilarious part of the story, and the part most unlikely to ever happen.
Also, the implication that an increase in the power and influence of Protestants and Catholic would lead to the downfall of a nation is pretty unrealistic.
Historically, Christianity in both its Catholic and Protestant forms, along with Hellenic and Roman traditions, have been strong and influential cultural and political forces in the rise of Western Civilaztion. The Enlightenment occurred in the Christian, Hellenic west. "Christian" nations such as Britain and the United States achieved the last several centuries' great works of medicine, architecture, engineering, botany, biology, theoretical mathematics, etc.
Going by track record alone, I'd say a parody based on Islam's power to drag down great nations would make a lot more sense. See also: Communism. Of course, in reality neither of those are very funny at all.
This, on the other hand, is an excellent Catholic joke, based entirely on things that are actually true about Catholicism:
One day, as Jesus was preaching in the temple, some people brought before him a prostitute. They demanded that he pass judgement on her, and condemn her to death by stoning. This was the legaly penalty for prostitution. Jesus would have to issue such a ruling in order to protect his reputation as a teacher of the law.
However, instead of condemning the woman to death, Jesus knelt and wrote something in the dirt at his feet.
Then he stood up and said, "let someone who is without sin cast the first stone".
No sooner had the words left his mouth than a rock came arcing over the heads of the assembled crowd, and struck the prostitute right between the eyes.
"Mom!" Jesus exclaimed. "Stop doing that!"
