So some people want to stay an Academy Student, it's actually good thinking if you ask me. Because Chuunin who attack them can get slain.
Anyway, you don't know the full reasons as to why someone would want to stay an Acad.
They could be trying to get their stats right so after they reach Genin, they aren't the onslaught of Chuunin and Jounin, not many people love the "rushing into your next DK".
We've all been there, we've all been slain by an acad when we were Genin and Chuunin, no big.