Is there a particular person that grates your nerves with their imposition of religion or are the insults primarily from groups?
My sister-in-law has said before that she isn't concerned with the facts and prefers to go with her gut. The rest of her, um, "blessings"(?) seem to stem from that.
In Sunday School as children they are taught the saying, "Jesus said it, I believe it, that settles it" -- or the variant, "The Bible says it, I believe it, that settles it". This allows them to un-ironically elevate dogma above facts and reason. And since they believe that god uses their "gut" to communicate his will to them on matters that are not specifically addressed in scripture, that's not much of a stretch either. Especially when "mere" human wisdom is actively decried by the Holy Book. "Trust in the Lord and lean not unto your own understanding", etc.
Life is too short to spend it constantly "grated on" by such things. Just let them be as they are and move on.