Yes, Eddie and I are well aware of that one. He doesn't learn karate, he learns kung fu.
So they briefly thought of calling it "The Kung Fu Kid." But that would have defeated the purpose of remaking the film, which is to cash in on nostalgia for the original by using the title.
So they went back to "Karate Kid," which is apparently what the other kids call him, as an insult, since they consider it an inferior martial art. Which I have no doubt the producers hastily inserted into the film as a reshoot so as not to piss off their core audience, which knows the difference between the two.