It means nothing when bruce lee is faster, can read his every movement, is a master of countering, can hit with killing power in 1-2 blows, is strong enough to literaly pick him up and throw him(if he wanted), is as agile as an olympic medalist/trained in the art of falling unharmed(should batman try to flip him/throw him), is as in tune with his surroundings as batman is, and is even more of a dangerous fighter than batman can dream.
Simply put, you can throw those" he did this to superman" or " he did this to whoever" at me, but that's just how bad the writing is for those comics.
That or he basically, cheated by using krptonite or some other weakness.
So what if he was taught by make pretend masters, bruce lee was taught by real masters, then developed a style of fighting that would beat the masters that taught him.
Bruce lee is like a world champion's best fight day on super soldier serum.
He would clobber bruce wayne til there is nothing left, but a bloody body on the ground crying for alfred to kiss his boo boos(wounds).
Lee:"get uppp you sissy. I want to fight some more. I want to see how fast I can knock you down this time."
Batman:"Save me, Alfred!"
[Batman looks up to see Alfred has taken off running in the opposite direction.]
Batman:"Robin,help meeeeee!"
Robin:" Motha****a are you crazy!?! Hell no! Have you seen what that dude did to you!?! I don't want no part of that!"
[Chappelle peeks his head around the corner]
"dAMN bATMAN! hE ****ED YOU UP, *****!"