Nobody said they did. What it points out is that Danzo couldn't defeat Sasuke despite himself being at 100%, whilst Sasuke wasn't. His KA usage was so poor that even an average Jounin detected something amiss.
KA? u mean IZ?
and if you're referring to Karin as an "average jounin"..... her fighting ability has absolutely nothing to do with her ability to sense and deduce a jutsu
Sasuke has a DMS Danzo, who inherited no special KKG or any special jutsus besides his easily countered Izanagi, should be an easy kill for any skilled ninja.
Theres a large list of people who can beat Danzo, so Sasuke barely beating him isn't that special
edit: u know what..... i don't wanna argue. I actually really like sasuke so its not my style to put down someone who doesn't deserve it so disregard anything negative i said about him.
but u are wrong about Karin being average. she's and average fighter not an average sensor/tactician