I think he's saying that Garen's passive doesn't make sense for his role. I'm inclined to disagree, being one of the old Garen players that jumps in, spins, kills someone with my R, then spins back out to hide in a bush for a while and recover all my health because Garen.
Aha. He also doesn't think it's very useful. Again, Garen's not made to stand in a fight forever. he's almost a hit and run type. If he's main tanking, he's going to use his W and rely onthe large amount of health, armor, and MR he's probably built. But even then his passive is useful, since if your team disengages at all and Garen stays out of trouble he's going to have more health for the next fight and won't have to back for it.