Lies.
A minority of Zoro fans perhaps believed only that, but a vast majority put the shogun on a pedistal as one of the strongest swordsman in the world.
Zoro needed to fight him.
At one point, King and Orochi appeared and King was the chosen one.
Then Kyoshiro appeared and him and King were obviously going to be both defeated by Zoro. And of course he would slay Kaido above the flower capital too.
Chapter after chapter Zoro fans lost everything (more than any other fandom probably).
Now all you have is Kaido, Luffy's opponent, and a strong link with Orochi