This comment is a perfect example of an arrogant know it all. There are many reasons to not want a headset, and they’ve been discussed here.
On another note, do those who choose to use their own headsets have the courtesy to put the airplane issued mic jacks back when the flight is over? Far too often I see them stuffed all over the cockpit. Put it back where it goes, if you choose to bring your own, non Boeing issued equipment.