With the amount of bad tanks in fp's, I would ask for a guard immediately as a dps too. Maybe he didn't realize you were geared and/or didn't see the title that confirms you are an experienced tank. I've seen plenty of tanks who seemed geared due to having some dread guard gear due to legacy smuggling. Heck, I have a healer at lvl 38 who is going to be full black hole/campaign once he reaches 50, but that doesn't make me a good healer.
How about, if I'm
tanking, *I* decide who to guard and you just shoot/stab things? If someone is too stupid to realize they are significantly out-geared by the tank and can't even read the title, why should I bother listening to their insipid advice?