Meowlegend
CelebrationMK10
Weapons always tend to have different damage types despite functioning almost identical. It is not an issue, since Terraria does not have deeply explained classes and just have damage types.The spear subclass includes multiple different types of polearms just like how swords include maces, sticks, living creatures, frying pans, canes, etc. To be more precise, the spear class is made out of polearms not spears. Spears are a type of polearm and lances are a type of spear.
Throwing weapons like knives and throwable spears tend to switch between melee, mage and ranger depending on what's convenient. I personally don't have an issue with it since at the points you obtain throwable knives and spears for melee, you have boomerangs, flails and projectile swords with similar range, though it's indeed kinda weird how throwing weapons don't have a well-defined class.
While Terraria does not have deeply explained classes and rules as to what determines a weapon's damage type, it tends to have some unique stuff shared by almost every weapon in that damage type. Good examples are how most of the melee weapons getting stronger in point blank range, minions always dealing more damage than a whip or Ranged weapons getting most of their power from the ammunition.
By the way, I do agree with you that there is not a need for throwable spears or knives for the melee class when you can make more boomerangs, or something similar. Daybreak, Vampire Knives and Shadowflame knife can keep their unique design as the only weapons like themselfs.
I am not gonna lie, I think Daybreak deserves to be a thrown spear than a held one. It is my second favorite weapon for that reason, I like its unique thrown spear nature.Rather than add a third pillar weapon that's a spear, why not make the Daybreak act like a spear with one click and like a javelin with the other click?