You know the difference right? If Ace was stronger, close to Oden's level. WB would allow Ace to go there. Thats why WB was angry since Ace wasn't top tier yet but wanted to fight top tiers. While in here most people think Mihawk is a top tier like Yonko, so you can't compare this to Ace.
Also fighting Kaido at Wano, and fighting Kaido outside of Wano are 2 different things, thats why WB didn't attack Kaido because Kaido had Wano backing himself up, Shanks wouldn't attack Kaido at Wano as well, he stopped him outside of Wano.