Did you know not performing as you think another player should in a group

[Jijifli]

Snip

I literally had a thunder mage leveling my ninja and I found it so irritating. I tried to explain and help but was met with the usual complete silence. I'm just confused on how people honestly play that poorly and not realize how much they hold a party back. I get not performing the rotation perfectly, but doing so little that their death doesn't even slow down the boss fights?