Where's your proof of that statement?
Is that why the Gorosei were pissed at his defeat ? Is that why the Bowler Hat Guy was forced to make Luffy lose and Kaido win ?
Kaido losing is the "Worst Case scenario " for the Gorosei.
Why are you acting as if you've seen the dialogue. You don't know context. GB wouldn't do a thing if Kaido is around. Doesn't mean he can't. Again Kaido has immunity and is untouchable due to the Weapons operation.