Hibachi's a Cave TLB. You have to judge them by different standards than most bosses. I mean, when the stage 5 boss shits you out by throwing fireballs you can't dodge without precognition of course it's frustrating. But Hibachi is a True Last Boss. He was designed specifically to say "you wanna 1cc my game? Well fuck you, pry it from my burning mechanical hands." Going in with the intent of doing well is the wrong strategy. Going in with the mindset of "I have a ridiculously hard boss and unlimited continues, let's see what happens" brings great joy. I mean, cursing him for being hard is like cursing rain for falling, it's what he does.
As for the fight, there's only one part I'd actually call unfair, and that's how during most of his attacks the slowdown abruptly ends, leaving you to dodge the last shots with a disoriented feel. The rest is just deliciously hard.