I guess it's a "saying" because I've heard it for many years from many sources. Point being, folks love to rag on people of faith, but can't recognize the many things they take on faith as well, often without thinking about it. Too bad topics like this degenerate into dismissive snark instead of thoughtful interchange, but probably not the best forum for tolerant thinkers.
Another saying; Opinions are like assholes, everyone's got one and they all stink.
I still like mopeds..... and mopedders, regardless.