Since when was it the Tanks job to explain fights?

[Jatoi]

It is not the tanks "job" per say but usually the tanks know the most about the fight because of mechanics they have to deal with but it is really everyone's responsibility to help people out. I always step up if someone else does not and someone wants it explained. It is just good manners to be helpful and so I try to do my best to help the group whenever I can and if I know enough.

Tanks usually know quite a bit about the fight but they also get a lot of flack if they don't babysit sometimes. The expectation of hand-holding adds to their stress on top of having pretty visible, necessary job that's high in demand.

I agree though, everyone ought to pitch in and doing so helps things go faster too. It wouldn't hurt to look into a guide either before going into a dungeon/raid, either.