I do not particularly agree with the OP either, when I were a lad I liked grim and gritty games and grindark worlds. Now, not so much so, I would play Dark Heresy as a one off but I doubt I would play a campaign. Why? Lots of things really, but to get back to the original point, when i liked grim and gritty it made no difference if I was DM or not and neither does it now when I do not care so much for it.