User blog comment:Fliu/Chapter 981: More Welcoming Arrivals/@comment-108.83.222.210-20200607201813/@comment-108.83.222.210-20200608203548

Apoo should really hope he has something other then his devil fruit abilities up his sleeve if he wants to come out of this alright. The alliance wearing the "Invisible Symphonious System" could render that ineffective. As for the other comment, it seems that underestimating the Strawhats tends to be done either out of individual pride or strong belief in the protection of someone stronger.

I recall how in one anime after a group of antagonists defeated the protagonists in their first encounter, the leader stated that their enemies would never be as strong as them and consequently would never be able to win against them. On the next occasion when only two of them faced the protagonists, one of them died and the other was forced to retreat. That forced a change of attitude really fast.

In this case, the lower members of the crew are mocking Luffy because they consider Kaido's protection to be their shield. They expect him and his commanders to protect them from anyone who can threaten them and thus it has instilled in them a confidence that they can easily deal with any opposition. The mere mention of a Yonko's name is supposed to cause would-be opposition to flee so they are clearly unused to people who attack them brazenly. Who's Who seems to disregard Luffy and the others as a threat likely due to his high ambition and his belief in Kaido's Strength. He might also disregard it because Queen has been noted to acknowledge Luffy's strength and the ambitious member of the Flying Six seem to lack respect for the current All-Stars. Queen and even Kaido seem to have noticed Luffy's strength as shown in their attempts to break his will and recruit him. Likely the same thing was planned for Kid. Just my opinions here.