@Antmrm
they don't just ''think'' it they get hyped because luffy manage to beatdown kaido and they learn a few tricks from it, also their own crews are strong we just don't see that power yet.
about ice-boy the key is on the same chapter, it just says ''we all profit for having our own agendas that make us pirates'' take an example, zoro swordmanship, nami navigation, chooper medicine, robin liberty etc... Kuzan is getting its own agenda now, that is liberty and not be bounded whit the mistakes of other people, just as it says he ''kills'' his own friend and the fate of a child and have the burden (talking about robin and the giant guy) he don't want to do it but still do it because was a order and a job.