Because CN is just so fickle with their shows. Sure, you all love JLU and it was a good show but it's schedule was all over the place, it had long breaks. CN also doesn't nurture it's shows the same way Jetix/ABCFamily does/did. They played current and past seasons, they really went for it. CN will just play whatever is relevant and has ratings and dump the other shows without thought. KRDK, even if it does get good ratings, will probably suffer from scheduling musical chairs and CN will probably just toss it out and never air it again after a few years. At least Jetix still plays all your favorite reruns. CN sparsely plays any reruns (in order, unless it's a mega hit show like Dragonball) and shows have come and gone like the wind on the network. JLU's end came and went in the blink of an eye, without the slightest warning nor a rerun despite it being a good show. Same with ReBoot. ReBoot was such a megahit on CN that they ordered more seasons! A new 4th season and the conclusion of season 3. But did it's ending get jusitce? No, Season 4 was only aired once and forgotten immediately, ReBoot was just tossed away right after.
I just don't feel CN would treat KRDK right. At least with a network like Jetix, we know that they would (for better or worse) continue airing the season long after it was done.
Did you see how badly their Saturday morning lineup bombed? Man, imagine if KRDK had aired during their saturday morning run. It would have never returned. CN always risks good shows with poor assed scheduling then blame the show.