Despite the risible style of the tracts, we could continue to consider more seriously what he says and why.
I suspect these tracts are popular at the moment (if indeed they are - and I have no reason to doubt you all) partly because of the current fascination with conspiracy theories of church history, as popularised especially by such writers as Dan Brown ("The da Vinci Code") and a number of others. They appeal to the desire to know things which are being carefully and sinisterly kept secret through the ill-will of powerful people. Linked with all this is the current turning to the late rejected 'gospels' rather than the divinely given canonical ones.
I have not taken the trouble - for the interest is not there - to check the sources and the 'facts' Chick sets before us, but I strongly suspect it is all a mixture of truth and falsehood. There is little to object to in his final conclusion; indeed, a good deal of truth. The truth in the mixture makes the falsehood appealing and credible.
Also, it seems that we could say without undue arrogance that he is not writing for a carefully thinking, seeking public. Let us (for the sake solely of argument) assume for a brief moment that all he writes is true: even then, his would not be the usual or proper route for a sincere seeker after God and truth to come to a knowledge of the truth. His style is directed at the gullible, at those (I suspect) who already wish to be led in that direction, rather than at those who wish to have facts and cogent arguments set before them so that they can prayerfully and humbly reach their own conclusions.