While I think OP expressed it terribly, I get the sentiment behind this thread. I think tanks and healers should DPS during downtime/rotation, but it's when DPS expectations are forced on them is where the problem comes in.

I play tanks to be a meat shield, to be a wall and to laugh at any damage thrown at me. But I've met too many players who grief me or other tanks when the tank doesn't get X amount of DPS numbers in ACT. Sure, in Savage where a slim margin exists between success and enrage, it's warranted. But in Expert roulette, players should feel free to DPS as comfortably as they like (which is where I've seen those types of interactions).

It's a small amount of times I've seen this happen, but it's silly to expect DPS numbers out of a non DPS role in anything but Savage and maybe Extreme.