Question

If an author wanted to ridicule a religion or a belief without being rude and straightup calling it "stupid," how could he or she do it?

Answer 1

She could use euphemism it is a figurative language that is used in place that can suggest something unpleasant but in the kindest way possible.

Answer 2

You can simply disagree. For example lets use the Church of the Flying Spaghetti Monster. I dont agree that the climate changes result in hurricanes or earthquakes based off the number of pirates available to hijack cargo ships. I believe on scientific facts that I have been presented with and that can be proven.