Obviously unfamiliarity can be unsettling, but you're wrong to dismiss a central theological difference as mere unfamiliarity or xenophobia. The Protestant Reformation - with key points, sola scriptura, solus Christus and sola fide - was kind of a big deal, you know, and those points mark absolutely central - and very meaningful to adherents of both sorts - differences in the whole theological model. Silly to dismiss the method to the whole point of those religions as short-sighted temporal blindness. To be clear, I'm not taking a position on the rightness of either one, or the knowability of the answers they believe in. I'm looking at two theories and noting that there's more to it to believers than mere pettiness or fear or ignorance. There are doubtlessly those things, too, but there is an incompatibility that forces (and in fact did force) a schism. But your point is more a dismissal of faith as a concept than it is any particular belief, and tbh it sounds as though your own criticism criticizes itself.