That’s likely because most “Tanking” players don’t understand how aggro works. It’s actually possible to pull group after group into a defeat zone, however, this requires an understanding of how all of the ATs work and how the team operates. In Pick Up Groups (PUGs, which I play with a lot), a Tanking AT player should be able to work out the team capabilities within the first couple of mob groups. Any Tanking AT player that cannot do that is welcome to message me for advice.