Or maybe it's liked because it's relatively competent in itself, is fun to watch and hasn't seriously screwed anything up in it's story.
You're describing people who are watching OOO because it's new and it's acceptable, not people who
really, really like everything about it as a creative work. These are two different levels of affection that will produce very different audience reactions.
If anything is the Rider show equivalent of a bouncy ball pit, it's Decade.
Decade's first episode was worlds colliding, the universe beginning to melt, mass hysteria, and cities exploding. It was a srs bzns show that wanted you to enjoy the wangst and dramaz. It drew a very different sort of fan than OOO does and had a
really different talk thread.
OOO is a show that is mainly about laughs and fun and bangzoom fightin' thus far. The talk-up thread reflects this, people like the memes and running gags and zOMG awesome power-ups. There's some apocalyptic stuff going on in the background but for now that aspect of the show is abstract at best.
So that makes the Greeds just as incapable since they "force" serious into this show?
Judging from this thread, nobody seems to take the Greed seriously at all. I think that's completely consistent with the show's intentions.
The Greed are an exaggerated and cartoony. They pose a completely unreal and impossible "threat." Their backstory renders them far more pitiable than genuinely sinister. Some of them, like Gamel, were clearly meant to even be identifiable.
The Greed are perfectly at home in OOO's light tone. Gotou, on the other hand, tends to feel like a guy who wandered in from some other show and is very confused about what he's seeing.