How are you gonna still use the trash Squardo argument after FS user Luffy got blindsided by Kaido?
CoO needs to be activated, Squard was a trusted ally, Oda never uses the word HAKI to refer to what happened and this was at a time where haki was a pretty obscure concept to the reader and when Oda used to make it very clear when it was question of it or not
Headcanon. If you hurt a logia's real body they take the hit like anyone else would
Headcanon again, Oldbeard and Shanks literally split the skies though and they did it CASUALLY
Luffy was fully focused on Kaido in 1vs1 and extremely fatigued "barely standing" as per Yamato's own words.
He got blindsided by an external assasin involving himself in this extreme diff fight.
That is different to getting stabbed by someone far weaker than you in a 1 on 1 situation.
WB could detect Ace trying to kill him while sleeping when his haki was working properly in ch552...
Doflamingo can stitch organs, but characters who can phase their bodies into amorphous elements have no durability benefits... Oh wait we've seen haki users slash Akainu's neck and him be fine afterwards...
It's not headcanon, the WB that fought Shanks was not in the same heart attack prone, deathbed state. WB specifically laments the fact his haki isn't working in 569 saying he can't stop them, just before Luffy does it by accident, do you even read the manga bro?