The Invisible Pink Unicorn, The Flying Spaghetti Monster, Russell's Teapot, and similar objections offered by the rational-minded to the existence of God fail to persuade believers? Rationally and reasonably considered on their merits, the arguments for the existence of the Invisible Pink Unicorn and the Flying Spaghetti Monster should be as persuasive as any arguments for the existence of the Christian God. Why aren't believers persuaded?
Appeals to blindness, irrationality, or stupidity explain nothing. Having had a weakness for theistic arguments inculcated at an early age, a big part why believers do not find arguments for the Invisible Pink Unicorn and the Flying Spaghetti monster is that Christianity is an ancient religion.
If so many people have for so long believed that there is truth to Christianity, so this line of thought goes, wouldn't there have to be something to this religion after all? Consequently, this would mean that the truth and meaning of human existence has been known for a very long time. This would also mean that anyone desirous of meaning and significance to their life should make little or no effort to strike out on their own. In a rather self-serving way, Christianity also teaches that the price of error is incalculable: eternal torment for failing to heed the promptings of one's parents, teachers, friends, and colleagues, in short almost everyone.
Christianity should not be prettified. It's teachings should be presented for what they are: advocacy of cowardice, conformity, and surrender to fear. The rejection of rationality means adherence to the most ancient teachings of humankind: stick with what you know, mistakes will always be fatal. This is the basis of traditional societies: do not experiment because the safest and most certain knowledge is that knowledge that is already known, lived, tested, and codified into what everybody else already knows.
Following this line of thought, arguments and appeals of Christians to faith and revelation should be rephrased as advocacy of cowardice, conformity, and blind obeisance to what everybody else is doing.
The objection that Christians will offer is that they do not feel themselves to be advocating cowardice or conformity. They haven't formulated the specific intention of advocating cowardice or conformity: they mean well.
In "meaning well," they preach love but consign to eternal torment anyone not of their clan/church. They consider themselves virtuous in demanding sacrifices (abortion, Terri Schiavo, euthenasia, etc.) from others at no cost to themselves. Some people need an eternity to compensate for the paltriness of their lives in this world: these people are Christians.