I've really no intention of dragging this out but, 1: You're starting to get a bit rude, and that's not necessary. And 2: While you have some valid points, they are, in fact, mostly opinion based. Someone who doesn't do medium to big pulls isn't just "wasting everyone's time". Perhaps they're ensuring they don't overwhelm themselves, if not the party? THAT, if anything, is "properly" tanking. Not to mention if tanks were meant to pull at least 5 mobs, they'd be grouped that way, don't you think?

Fact is, no matter how much it may help a tank to be better by learning to pull/manage larger pulls, it's STILL not an absolute standard for tanking. Maybe an accepted practice, but not a standard. You are essentially demanding others play to your preferences and calling it "efficiency". This simply isn't so. Tanks hold aggro and mitigate threats to the party. DPS attacks/supports as necessary. Healers heal, support, and even DPS if/when possible. That's honestly where it begins and ends. All else is opinion-based.