Garth Ennis is the comic-books equivalent of a shock-jock radio DJ. He's deliberately offensive and gross on the level of a maladjusted teenager, TBH. He and Mark Millar are two authors whose popularity I will never understand, and Amazon made the right choice in trimming down the content of the series. It's still very explicit and dark, but in a way that is mostly not completely cringey and awful.
It's funny that you mention that because I've been a fan of both writers - Ennis more than Millar - so perhaps I can share my perspective.
Both of these guys rely on shock value at times and they can go too far; in fact some of their finest moments are from when they skirt the line. As such they've both created some amazing comics in the past whose serious moments are right there at the top with any other authors; Ennis' Hellblazer run is downright iconic, his Hitman was so fucking good and in my opinion he created penned the definitive Punisher run as well. Millar I'm more torn on; the first year of Ultimates was pretty well done and then he just seemed to get lazy or too carried away - the second year wasn't nearly as good, and then the whole thing went to hell.
But Ennis has a trait I've seen only rarely - in that way I'd compare him with Terry Pratchett. He can write these weird-ass absurd situations and focus on humor then he can flip a fucking switch and blindside you completely, pivoting into really serious characterization and dramatic, intimate moments for his characters.
I describe Katee's character as "Starbuck, if she had her shit together"
I know what all these words mean but what you are describing does not compute.
Ennis is much more palatable, even at his worst, than Millar is. Millar only ever works when he's constrained and toned down, and even then so many of the things he writes need to be cut. I mean just from your example-- Ultimates --I can pick a few things, like actually abusive Hank Pym (way worse than a slap which was anecdotally a misinterpretation of the script by the artist that they just ran with) and rapist Hulk, that the book would have been better without.
Unlike Ennis, Millar is basically limited to having interesting ideas that really should be left to others to develop.