Have a look at a 5e weapon table.
Notice anything strange about the Dart?
Well asides from being the only thrown weapon in the ranged weapon table other than the net, it has finesse.
But wait, all ranged weapons use dexterity anyway, and finesse isn't worded right to let you use strength.
So, did ranged weapons use strength, or was it a melee weapon?
The probable answer is that it was intended to be listed as a melee weapon that you simply can't use in melee, but then was changed last minute because that's confusing, but eh. *shrug*
Notice anything strange about the Dart?
Well asides from being the only thrown weapon in the ranged weapon table other than the net, it has finesse.
But wait, all ranged weapons use dexterity anyway, and finesse isn't worded right to let you use strength.
So, did ranged weapons use strength, or was it a melee weapon?
The probable answer is that it was intended to be listed as a melee weapon that you simply can't use in melee, but then was changed last minute because that's confusing, but eh. *shrug*