Violence, yes, but almost all of it is nonlethal kung fu or ambiguous army action. How much blood was there in the show? How many unambiguous deaths? I hardly think you'd say Hellsing is almost as easy to recommend, but oh darn has that one lesbian vampire scene in there.
I think the things that make Hellsing (Or more specifically, Hellsing Ultimate) harder to recommend would be the necrophilia, baby murder, cannibalism and absolutely cringey "comedy" scenes, personally.
I'm not seeing anything in his post to support this, though. Some people really, really don't like certain things.
I was mostly voicing it because, at that moment, I could not think of a single series that benefits from it.
Clearly Kill la Kill slipped my mind because, yes, that's a series that benefits from it. Not because it's titillating or attractive, but because it turns it into an actual plot point with meaning and a purpose, elevating it above cheap pandering.
The problem is that not many series do that; they shovel it in even when it doesn't fit or make sense just to fill some sort of quota that apparently animation studios and manga artists seem to be under.
War, yes, but again, ambiguous and clean; lots of implied KOs and mostly army vs heroes combat. I hardly think you'd say Saving Private Ryan is far easier to recommend, because while they both have war SPR doesn't even have any women and therefore has even less fanservice than Avatar.
Abusive relationships haha oh god yes, but almost all in the past and centered on the designated tragic backstory character. I hardly think... oh fine, I'll throw Neo a bone. I hardly think you'd argue Familiar of Zero would be just as easy to recommend as Avatar if not for all that fanservice.
Politics, yes... but again, none of it especially unpleasant. I hardly think you'd argue that... what, The Godfather, I guess? I'm having a hard time thinking of what you'd have difficulty recommending because "politics," but I'm sure Avatar's are remarkably nonobjectionable by comparison.
Betrayal... I guess? But again, usually of the HAHA NOW YOU'RE IN MY PRISON WHERE YOU AND YOUR FRIENDS WILL NOT ESCAPE LATER IN THE EPISODE type (if not the "I'm supposed to be on the bad side but just this once I'll abuse my position to help you guys escape" kind). I hardly think you'd argue that Running Man would be just as recommendable if it wasn't for the dancers and leotards.
I would say the difference is that these topics are generally not there to pander to an audience in a cheap manner, instead they are part of the theming or plot and serve to drive the story forward (or to give a story in the first place). Not always, but generally.
Violence is, however, often used in a very cheap and sometimes disgusting manner to put asses in the seats, as it were.
Personally I find shows like Elfen Lied, Mirai Nikki, Gantz, and their ilk to be rather grotesque in a very adolescent and immature manner that completely puts me off, and in a far worse way than any fanservice.