Yeah people who watched Korra after it was all over will never understand what it was like to experience the first season after all the hype that had surrounded it.
This was back when ATLA was universally adored, and we didn't nitpick it nearly as much as we do these days. And now, here was a sequel series to Avatar that had so many cool-sounding things about it. A waterbending Avatar! A female Avatar! She was going to be headstrong and aggressive! The show takes place in a steampunk city powered by bending! There's a sport that involves bending and we're going to get a tournament arc! There's cool turn-of-the-century stuff like filament lightbulbs and radios and old-timey automobiles! There's going to be Asian-inspired jazz music! We're going to get gang warfare!
On and on and on, so many cool little details came out about Legend of Korra. The hype when the first episode came out was out of this world. But it all came crashing down as the show actually aired. Pro-bending was fucking awful and tedious. The love triangles were infuriating. The reveal about Amon totally ruined him. And that last scene, where Aang literally shows up to hand Korra her victory on a single platter, and THEN Mako (who we all hated by that point) shows up to kiss her. It was one of the most rage-inducing things I've ever experienced live.
The reason /co/ hates Korra as much as it does is precisely because many of us still remember how excited we were in the buildup to the show coming out. It's like marrying a beautiful woman, then finding out she's cheated on you. No, it's like marrying a beautiful woman and then finding out she takes dick regularly every night behind the 7-Eleven. It was like someone killed our dog in front of us.