Momonosuke hits greenbull with a blast, this makes greenbull believe he has to get serious. Serious vs Momonosuke, mind. Momo. Then, he senses Shanks' conq from off island and decides that, nope, he's out. But he also remarks after fighting momo that if Kaido was here, he wouldn't have come.
How after all these things can you still try and twist this in any way that doesn't make Greenbull look like fucking fodder? Just accept the L, even if greenbull is pure fodder Akainu is still strong, you don't have to defend this plant pussy so much.
Give it up already.