Perhaps the true test of a libertarian would be to ignore the actions of oppressive states and ideologies; to simply shrug and walk on by when, say, neo-nazis are on the rise, or when tyrannical regimes repress their populations.
Perhaps the true test of a good person and a humanitarian would be to ignore the manifest injustices and suffering in the world.
I'm an atheist and I find religion fascinating. The good and ill that have been done in its name I carry in my genes, from the vespers of Monteverdi to the pogroms of the Ukraine. It's too big a subject to be ignored.
So the argument of the original post doesn't hold water for me.