good luck ranking in google and explaining your self to your md when your major publishing site takes 20 seconds to load I wont mention any names but I know of two cases of this.
From experience where there is jquery there is normally at least a dozen other js files cut n pasted at random along with a similar number of css files with no thought to efficiency - hell most sites I se they can't even optimised the godamm images using Photoshop properly.
"JQuery is bad because some people who use it do unrelated things wrong"? Should I stop driving because some other people who use cars happen to cheat on their taxes?