I thought them being dismissive was largely due to the guy saying gems like "30 episodes of characters doing nonsense" or say that there was "nonexistent character development", and pretty said the entire anime disappointed him. I dunno about them, but I read critiques like that that come as them watching a completely different show, it's a lot harder to take it seriously and make you not even want to bother getting into an argument. I myself won't post GIFs (unless the critique in question is truly ridiculous, then maybe ;D), but I do tend to not feel like giving a substantive reply, assuming I reply at all. But you're right nonetheless to an extent.
Anyways, all I can say is said "nonsense" serves the plot later on, such as the Cinderella episode providing a future escape route for Kira for example. Or the silly episode where we meet Shigechi, a character that became the driving force for getting our protagonists to go hunt down the town's serial killer.