Darius's advantage?

So in league there are abilities called channels. Channels are usually just a channel where the champion cannot input movement commands while casting without interrupting the ability or they just cant move at all. With being an exception to this. But every single channel can be interrupted putting in on cooldown or reduced cooldown, well that's what we would love to say for the sake of consistency. Then we have cast times such as which are some of the longer cast times. But these can be stopped by abilities, spell shields, or items. As far as well know all channels can be interrupted with exception to two... one being when he is dead but that is just part of his kit and ability. Now we have who while having the shortest channel time lacks any real clarity.Being of the only channel times that WILL refunded both cooldown and mana fully if interrupted this messes up any clarity to the design of channels. Almost every single ability in-game can be stopped by with exceptions to abilities that do not have cast times or channel times and are single target lock-on. So why does every single ability one of these ablites go on cooldown when someone uses correctly on them EXCEPT for . is the one inconsistency in in all of league and maybe there is another Im not seeing. But why oh why does this one ability ultimate or not gets a pass? For newer players who are starting to learn the game this is the only ability that does this making using just more confusing for starters! So maybe there is something i'm not getting but making this except for the "Dream of getting a Penta" more delirious if anyone deserves a penta its