So Denjiro fake his respect towards him
You saw that panel there. All the scabbards were telling Kin'emon he was lying but Denjiro thought Kin'emon was tough shit.
Yer they never said anything. Kin'emon remained the leader after his hype as a master strategist was proven false.
The scabbards clearly don't care. They just like Kin'emon. He can be weaker (as he is) and they still let him be leader.
It's like a Mafia gang. The leader of the gang doesn't have to be the biggest and baddest guy.