Why does okonkwo refuse to show affection to ikemefuna, even though he feels it?

Okonkwo himself grows quite fond of Ikemefuna, but he does not show any affection ... he considers doing so a sign of weakness, which he refuses to tolerate in himself or others ... Even though he knows that they are too young to understand farming ... Okonkwo is very fond of Ezinma but rarely demonstrates his affection