Probably because it's not filled with a bunch of punches that barely connect and look sloppy as fuck.
"THEY CUT THE CAMERA MORE THAN ONCE PER FIVE SECONDS" isn't a great critique when we're directly contrasting it to a garbage fight with a villain doing a John Cleese impersonation through a bass amp looking like he's a grandpa fighting his chess buddy.
This is a bit strange. If you watch plenty of martial arts movies you will notice that a lot of fights (mostly 1 v X) tend to become kind of lol worthy. Ever watch The Raid 2 where at the end he storms the restaurant and he throws an empty water jug at a guy and he literally falls down in completely agony for about 2 minutes as the protag fights people? Or in Raid 1 where it's 2 v 1 and one kind of goes off-screen for a little to wiggle in agony? A lot of fight scenes don't actually make a lot of sense as you go for the spectacle while adding in what makes the characters unique IE Bourne using random house hold items to emphasize his cleverness and quick thinking. Just because WS does a knife flip, or they have connecting punches doesn't automatically make a fight good. It's more about how its staged, shot, and what it adds to the story. You have to remember that a fight scene is more than just punches but part of the overall film. If it's just a fight scene just because the movie NEEDS a fight scene then it will always peg a bit lower. This is pretty true for a lot of blockbusters that just throw in action as if it's just needed because a focus group got bored.
Like, Eli vs Agent in Boardwalk Empire is a way better fight scene than TWS and it's literally 2 dudes brawling in a living room because, as I've said, it's more than just how flashy the moves are.
Edit: To compare even fights scenes online, Bane v Batman has 14 milion views while Cap v TWS has 1.3 million. This just shows how forgettable the action kind of is for a series THIS BIG. The Raid, a MUCH SMALLER film, has more views for it's drug room scene (1.6 million). Jaka v Maddog has 1.8. Raid 2 has millions of views too. I don't believe that TWS had that much of an impact on viewers as a lot of people think it did. For a big franchise, no one seems to really care to go back and rewatch clips of it.