Arguing with protectionists is very much like swatting helium-filled party balloons. Like these balloons, protectionists are full of much gaseous stuff, yet are largely without substance. Thus, both are exceptionally lightweight, slow when in motion, and, hence, easy to swat down. But also: largely because balloons and protectionists lack much substance, both are virtually immune to damage when swatted. When hit, no matter how solidly, they simply float back up into a nearby space and continue, lacking any real substance, to be exceptionally lightweight and slow when in motion.
Another similarity is the unfortunate abundance of protectionists. Helium is the second-most abundant element in the universe. In the universe of human cognition, protectionists are astonishingly abundant carriers of economic fallacies.