In Africa, there is a great distrust of the ICC. The consensus among African leaders is that the ICC is a tool weaponized disproportionately against African leaders. On multiple occasions, African Union members have contemplated carrying out a joint mass withdrawal from the body.
The other reason for the loathing of the body: African leaders typically have poor human rights track records. Many know that they are all at risk of indictments, and sticking together makes sense.