If only we believe hard enough we'll make it somehow. So goes the popular chant. What you believe is not important. They perish because they refuse to love the truth and so be saved. For this reason God sends them a powerful delusion so that they will believe the lie.
Faith never means gullibility.
Credulity never honors God. The healthy soul, like the healthy blood system, has it's proper proportion of white and red blood cells. In the healthy heart there must be provision for keeping dead and poisonous matter out of the life stream. This the credulous person never suspects. Each one should be fully convinced in his own mind.