Shanks is always pushing the boundary for CoC/Haki. He's always the one Oda chooses either by name or literally by display, to show a new level of raw haki.
First one to show an animal being intimidated with a glare
First one to show characters getting knocked out
First one to show physical objects being damaged with CoC burst
First one to show raw haki affect another top tier, and from miles and miles away
We literally saw Yonkou Whitebeard, Kaidou and Big Mom throw out attacks all the time, it took Shanks his first named attack and everyone around him was passing out from DD, nobody did it like that. They had tons more panel time, entire sagas to show something like this. Even Garp who came AFTER Shanks on Hachinosu did not do this, Shanks knocked out people from the collateral raw haki leaking out from his physical attack. He's on an entirely different level when it comes to CoC display.
I don't know why this fanbase deludes themselves so much, If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck.