Why is it wrong to have a hostile view towards God and Christianity?

[Okay, maybe Mike Johnson is a competent parliamentarian.]

If hypocrisy of a few individuals is enough to invalidate an institution or belief system, then by that logic the entire tradition of secularism deserves to be chucked into the toilet.

There isn't really "a" tradition of secularism, though, is there? Japan and China are both mostly irreligious societies, but the prevailing ideas about humanity, the cosmos, morality, etc. are very different between the two countries.