Holding threat isn't anymore involved than remembering to turn tank stance on when you start an instance. Not dying to tank specific mechanics or damage is little more than using some ogcds when you see the big red indicator or pull the two packs before the gate.
SE has trivialized tank specific mechanics. Most of a tanks gameplay consists of doing dps. How can you claim then that they should not be concerned with that element of their gameplay? How can anyone seriously claim that holding threat is a primary element of the job at this stage in the game? It's an absurd statement.