Arrow from dispenser deal same damage at low velocity

Description:

Arrow that was shot by dispenser deal same damage whether on high or low velocity.

Steps to reproduce:

1. Load a survival world with a friend

2. Get a dispenser, Arrow, And a bow

3. Place the dispenser facing down at 20 block above

4. Stand 20 blocks below the dispenser

5. Try to activate the dispenser

6. Then compare it with arrow that shoot by a bow/player from 20 block above (may need friend)

7. See the damage/heart loss difference

Expected result:

Arrow that shoot from dispenser deal damage that affected by velocity (like arrow that shoot by a bow/player)

Actual result:

The arrow deal same damage no matter if it just fall from 1 block above the target