Don't get twisted by /co/ on what happened. When Korra was announced as a mini series /co/ was seriously hyped. I mean we're talking about threads again and again as release got closer. People were making up all crazy and cool theories and ideas as concept art kept getting released, and it was actually very fun. Episode 5 Season 1 is where it started to go to shit and people got super pissed, but not everyone. To sum it up many people dropped Korra after Season 1 or even before the finale. People were just upset at potential squandered, but don't think everyone or the majority thought Korra was shit or unwatchable. Season 2 finishes and it turns into dog poop, by the end of Season 4 I'd say Korra was disliked by the majority of /co/. Though I'm sure the numbers between positive and negative were somewhat similar. In reality many people who dislike Korra are disappointed by the potential it had. Also many regard it as forced pandering (verified by storyboarder for the show) but to what extent it would be hard to say.
Korra is not a bad show, but it isn't good either. It's squandered potential and that's why /co/ is still bitter about it. Also lots of the people who viewed the show positively don't really come to Korra threads now. Partly due to there being a huge influx of viewers outside of /co/ participating in /co/ threads.