If you refer to arguing with people who have little chance of changing their mind, I do it all the time online. Ranging from the racist subs on voat, the vegan subs on reddit, and other "mystical belief subs".
The problem is people assume a single argument is enough to spark change. People become defensive and cut off in the course of an argument they are losing, and resort to commonly repeated phrases and terms to defend themselves.
What debate does is ignite a spark, and if the fuel is there, it will grow into something more, even if it takes months, or even years, to do so. Arguing with pigeon's are absolutely worth it, because the pigeon, after strutting around on the board, does understand it didn't really win.