Why do we hand on the baseline

[BLS]

I don't have an answer, but have the same question.

For two-man, the Officials Manual says
- Hand the ball if throwin is from the front-court end-line.
- Bounce the ball if throwin is from back-court end-line and there is no defensive pressure.

Seems the direction is to hand the ball if there are defenders around - but leaves me wondering why.

For three-man, back-court end-line throw-ins aren't specifically addressed.