Other mistake: After the song 'Love Will Find a Way' when Kovu and Kiara are peering into the water and Kovu says, "We are one," in the reflection the scar on Kovu's face is on the wrong eye. Nothing to do with it being reflected, it was on the eye nearest Kiara, and now it's on the other eye.
Other mistake: Near the start of 'Not One Of Us', animals are stomping their feet at Kovu. There is a gazelle towards the bottom right-hand-side that does this while raising both front legs and having their hind right leg not on a proper surface (looking closely, it's actually floating on nothing). No animal could do this without falling over.
Answer: In real prides the males are kicked out once they reach maturity so that's idea that they kept in the movie.
Disney-Freak