In the "Xiao" organization, he is the only one who works with sharks. This is because Hoshigaki Kisame knows Uchiha Itachi's past, and he has the same experience as him.
Because of the same experience, Hoshigaki Kisame's impulsive and decisive style of doing things was also created. When Uchiha Itachi took Hoshigaki Kisame back to Muye Village for the first time to "send" information, Hoshigaki Kisame wanted to follow Uchiha Itachi to complete the task, but he didn't want to know anything else and why. In addition, when they entered Muye Village, they met Sarutobi Asuma, Sarutobi Kurenai and Hatake Kakashi who came later. A fierce battle made mackerel have a good time.
Mako fully enjoyed the fierce fighting with Sarutobi Asuma and others, and didn't want to ask more about the root cause of Uchiha Itachi's coming to Mu Ye Village. Because his impulsive and violent personality directly determines what kind of behavior he will have. If Hoshigaki Kisame pursues deeply, or finds something unusual, it is not in line with his personality.
If impulsiveness and violence are Hoshigaki Kisame's character and style, then calm self-defense and murderous look are Uchiha Itachi's superficial characteristics.
When choosing a partner, Hoshigaki Kisame had learned about Uchiha Itachi's "heroic deeds". By contrast, the number of companions he killed in the performance of his duties is simply insignificant. In any case, the whole race was destroyed by Neiguang, and the number can be imagined.
Although Hoshigaki Kisame is called "bijuu without bijuu", Hoshigaki Kisame still has to do his job honestly before Uchiha Itachi.
Because it seems that Hoshigaki Kisame can't beat Uchiha Itachi. Even though Hoshigaki Kisame's strength is already very strong, Uchiha Itachi's ability to assist and shine is not covered. Plus Uchiha Itachi has a murderous look to kill the gens, and Hoshigaki Kisame doesn't want to provoke him. Since I don't want to mess with Uchiha Itachi, I don't want to make trouble. Naturally, Hoshigaki Kisame won't ask about things beyond the task, and I won't guess the mind of Uchihiro. Unless Hoshigaki Kisame wants to go to war with Uchiha Itachi.
In fact, apart from Hoshigaki Kisame's personality, Hoshigaki Kisame ignored Uchiha Itachi's task because he believed and respected Uchiha Itachi.
Hoshigaki Kisame's belief is from the heart. The partner he chooses, from the moment he chooses, is doomed to what he will do. Maybe it's because Uchiha Itachi's deeds are too shocking, maybe it's because of other reasons, but whatever the reason, Hoshigaki Kisame has always been concerned and convinced by Uchiha Itachi.
It seems that everything Uchiha Itachi has done is right, and he doesn't need to refute or speculate at all. After Uchiha Itachi and Hoshigaki Kisame entered Mu Ye village, they fought against Maito Gai, but Uchiha Itachi stopped them, and Hoshigaki Kisame followed Uchiha Itachi's advice. Hoshigaki Kisame is convinced of Uchiha Itachi's analysis and exposition.
Even if there were occasional complaints, Hoshigaki Kisame never interfered in all the actions of Uchiha Itachi. Perhaps because Hoshigaki Kisame and Uchiha Itachi have similar experiences, Hoshigaki Kisame doesn't want to mind his own business!
This is why Hoshigaki Kisame turned a blind eye to Uchiha Itachi's behavior. So, what do you think of Hoshigaki Kisame's behavior differently? If you have different opinions, please leave your opinion in the comments section.