I don't know why people have such an issue with being called out on DPS.
If a tank fails to hold aggro/pop cooldowns for big hits multiple times, people call them out on it.
If a healer consistently lets people die, or runs out of mana overhealing or just doesnt heal. They get called out.
So why is it an issue to say to someone hey Mr DPS class, you're doing less DPS than a wet noodle, please refine your rotation?