The other 3 turtles weren't cool:Character Bios
 

In the theme song. It goes "Raphael is cool but rude". So It's clearly stating the other 3 turtles are not cool, with Donnie doing machines, leonardo leading and Mikey being the party dude.

How do you feel about this? Deep thinking.

Nobody has ever considered Don or Leo cool. Ever. Which is shameful. SHAMEFUL.

Is it "cool but rude" or "cool but crude"? I've always heard "crude" whenever I hear the song.

Gimme a break

How is the party dude NOT cool?! He's the PARTY dude! That's cool by default! Probably cooler than Raph because he is the one everyone wants to hang with and party with. Just sayin....

I never really got how he was the "cool" one, anyway. The Groucho Marx ham, maybe, but that's not really cool.

Okay, maybe to some it is.

They're all cool in their own ways.... Leo, cool in temperament (plus sword master, come on); Donnie, the cool tech savvy wiz kid; Mikey, the cool, fun party guy. They only say it for Raph so we know he is too... the others didn't need it pointed out. (zing!)

:P

It's "crude", which sums up OT Raph perfectly. He was crude and blunt. Look at that ep with the Star Child. They knew the kid was prone to tossing things around when upset and stuff. The kid was upset and crying going on about how everybody hated him. Michelangelo was like, "No, we don't hate you." Raphael, however, was like, "No, wait, I hate him."

So yeah...crude.

I think the lyric inserted "cool" in order to take the perceived edge off Raphael's rudeness. And he wasn't rude 100% of the time, suggesting he had a fairly mellow personality, rather than the hot-head he's so often portrayed as in modern incarnations.

You have to remember in the FW cartoon Raph is more laidback and a sarcastic jokester. People find that cool so that goes with this iteration of the character perfectly. But the lyrics definitely don't make sense with the other iterations of Raph.