All of the 3 last posts (before RK Joker) are close to horrible. I couldn't disagree more, seriously. I find the matchup close to even. If you have good reaction speed, battles against MK aren't supposed to be as horrible as you guys make them to be. Oh, and... MK's ftilt doesn't clank with Kirby's fsmash, and if MK holds shield, kirby can easily get a grab in, or he could also move away if he's at a dangerous % (enough to get SL'd to death).
Kirby can shieldgrab almost every ground approach MK dares to do, except his own grab, and that can be maneuvered. Spaced aerials which have their spacing reset because of a Kirby running in and powershielding (fairs/low dairs) can also be grabbed. Kirby can grab MK out of his tornado. Fsmash breaks all of MK's specials except grounded SL, and only because of MK's invincibility frames. Kirby's bair can compete with MK's range, and it's also easily refreshed by pummeling+dthrowing (or any other attack) the MK. MK can't edgeguard Kirby as well as he can edgeguard other characters, thanks to Kirby being light and having multiple jumps (unlike DDD, his weight and upB are his problems when he's trying to recover). Kirby's speed is decent enough to keep a safe distance from MK in case he decides to go on the defensive. He can heavily punish badly spaced MK moves. We might never get an inhale in (I never even try anyways, MK's range destroys Kirby's inhale range), but we don't depend on inhale. And kirby's utilt, ftilt and dtilt have deceiving range that can hit an MK who doesn't realize the hitbox extends as far as it does (or who doesn't know utilts can be spammed).
Plus, I have plenty of Mk experience. Not like ti matters when i say this, anyone can say "Oh, but you probably haven't played top-level MKs". Well, the top level MK in PR (HDL) retired a year ago, and i never got to play him... but I HAVE been playing against the 2nd highest MK in PR (and a few others), and luckily, he lives near me so we play quite often. And he and me both agree Kirby is a ***** to fight when you're using MK (remember he's gained Kirby matchup experience by fighting me as much as i've gained by fighting him... And i still don't see the 65:35).