These whole WB Oden situation.., the way I see it pretty simple actually...,
1. WB still regarded kaido as his old crewmate/younger brother even.., alongside with Linlin, there's undoubtedly deep emotion going on between them (rocks crew), I'm pretty sure.
2. Not worth it, if he just accepted it then he just lost Oden, if not then he'll lose even more of his family for the sake of what..?, vengeance..??, nah.., not worth it.., so he just swallowed the hard pill and move on.., too many casualties is dead on point actually. One Oden VS even more of his family..?, no brainer here...