Exactly. Thousands of years of wild claims with zero evidence are hard to get past.
At least with Santa there were signs. (Fake signs by my parents, I never trusted them again after)
while I agree with this, the analogy does have some flaws, namely there is an explanation thats concrete that explains how the presents get there etc without reference to santa clause etc, its not a viable hypothesis.
God as an anthropomorphic creature is obviously a projection as he would be the god of everything and why he would be human like, care etc when other corporeal but non-sentient things are technically in his image is flawed.
However, as to the question, why is there something rather than nothing doesn't have a great explanation. It also appears that logic, at least traditionally consistent/law of the exluded middle aristotolian logic cannot solve the question wihtout ending in aporias.