Tank Scaling still a massive issue

[Xtrasweettea]

[...] The only enmity problems that exist are if you try to play tanks like you did in 2.x and 3.x, e.g. sitting in DPS stance spamming DPS combos, which is not playing tank or managing enmity, it's playing DPS with occasional tank cooldowns.

I keep seeing this point made all over this board whenever there is a tank complaint thread or a pro-DPS tank thread on here.

Can a "Tank Purist" like you, Johnny, explain to me (a "Tank Radical") why it I am not considered tanking if I do swap to DPS stance (or drop Grit) and spam DPS combos?