If he has completely mastered every form of martial arts in the galaxy from the beginning of time until the 30th century, why would he name himself after a single martial art?

Because it's catchy.

Because Mr. Miagi told him so!

Because the 60s were great!

Because it sounds good.Karate Kid.It's alot better than Master of Alot of Styles Kid.....

Gotta love 60's stereotypes.

" If he has completely mastered every form of martial arts in the galaxy from the beginning of time until the 30th century, why would he name himself after a single martial art? "

"@Power NeXus said:

" If he has completely mastered every form of martial arts in the galaxy from the beginning of time until the 30th century, why would he name himself after a single martial art? "

Then why don't you figure out a better and more accurate name for him ;P"

Technically it could work if I (and probably a lot of other people too) didn't associate that with the planet more than anything else :P, besides, I like "Karate Kid".

"@Power NeXus said:

" @~The Wanderer~ said:

"@Power NeXus said:

" If he has completely mastered every form of martial arts in the galaxy from the beginning of time until the 30th century, why would he name himself after a single martial art? "

Then why don't you figure out a better and more accurate name for him ;P"

How about 'Mars'? The ancient Roman God of War, and the origin of the phrase 'martial arts'. "

That would work if DC didn't already have Mars (the Roman god of war) as a character. "

"@Power NeXus: Maybe karate was still popular when they invented Karate Kid. "

wax on wax off, sorry had 2 be said lol

" because Krav Maga Kid doesn't sound as good "

"@Emperor Gonzo Noir said:

" because Krav Maga Kid doesn't sound as good "

 Krav Maga Kid sounds much more awesome. ;) "

In 1966, Karate was still the most well-known martial art in the United States.  Kung Fu and its many romantic movies from Hong Kong weren't yet popular in the US.  Bruce Lee's "Enter the Dragon" wouldn't come out for another 7 years, and it would be almost 2 decades before the 'ninja craze' of the 80's erupted. 
 
So if you said 'Karate Kid' in 1966, everyone would generally get the idea of what you were talking about.

"because Krav Maga Kid doesn't sound as good "

That's his name because "Karate"  means  'empty hand'.  Pretty fitting for a guy who doesn't need any sort of weapons to beat someones a$$.

Because when you put "karate" and "kid" together they sound like a superhero. 
Or an 80's movie franchise.

" @~The Wanderer~ said:

"@Power NeXus said:

" If he has completely mastered every form of martial arts in the galaxy from the beginning of time until the 30th century, why would he name himself after a single martial art? "

Then why don't you figure out a better and more accurate name for him ;P"

How about 'Mars'? The ancient Roman God of War, and the origin of the phrase 'martial arts'. "