Rejecting irrational claims/assertions of magic and supernaturalism agents not at all irrational. Belief in a 6,000 year old earth, talking snakes, men rising from the dead, etc., umm yes, very rational.
Here are beliefs of some Americans:
Fluoride in the water makes people communist.
The earth is flat.
There was no moon landing.
There are lizard people.
Is this reason enough for anyone to reject all things American and move somewhere else? None of these are the backbone of America--they are simply what some Americans believe.
Likewise, a six thousand year old earth has nothing to do with the backbone of Christianity--it is merely a belief of some Christians--and some non-Christians for that matter. Nor is the belief in a literal talking snake required. There are several different, and accepted theories on that.
Rejecting any faith, including Christianity,
for silly reasons only results in the one rejecting it look silly. They end up being tossed in the silly box where some Christians and Americans are also residing.