I'm not gonna bother trying to prove that Kaido doesn't have a real title, because there is enough evidence about it already.
Instead I'm gonna
pretend that his "title" is real.
Kaido (World's Strongest
Creature) himself puts Whitebeard (World's Strongest
Man) above himself:
He needed to backstab Whitebeard who fought Navy, in order to eliminate Whitebeard
Big Mom as well puts Whitebeard above Kaido as well
So if they both value Whitebeard above Kaido, then that means Strongest
Man title > Strongest
Creature "title". Meaning that creature "title" has nothing to do with humans. Otherwise Whitebeard would've been called the World's Strongest Creature and not Man.
What does "Creature" mean? Simple-
animal.
Kaido is all about animals:
- His devil fruit is animal
- His whole crew is based on animals
- His smile products are based on animals
- His crew is called Beast pirates
- His epithet is literally called "King of the Beasts"
That's right, Kaido's rival for his "title" are animals. Kaido is just the strongest animal. This is why "man > creature (animal)".
It's the most pointless "title" there is. It's on the same level as Big Mom being the world's strongest hag. There is basically no competition for that "title"
You can see just from the way they died on whose title is the superior: