Your reaction is the best, just laugh at them! Because you couldn't possibly take such stupid people seriously, and I think this reaction irritates them more.
My dad does humorous poetry on steemit, he calls himself @beastlybanter. Even if poetry is not your thing, you might enjoy his last one called "Irritate An Idiot Day" its based on an experience he had when he was driving with my kids and I in the car together.