I don't understand what this means... maybe it's just my non-native English though.

IIUC, he means that orc scorchers would throw "throwing spears" instead of "orkish spears", etc.
And I don't think it's a good idea to waste new items.

Oh my. A non-player character that throws its weapon towards another character, is currently throwing a melee weapon. This suggestion is that the non-player character or spear trap rather shoots/throws a throwing-knife, throwing-spear, throwing-axe, throwing-club.

Regarding wasting a spot on the new items list. We have some of these weapons already, so we are looking at 2 new items being created: throwing-axe and throwing-spear(regular-javelin).

Also throwing weapons are underused, because of rarity perhaps. Having more generated through this suggestion, might change that. I mean what are you going to do with all the throwing-axes. They will suck as melee weapons. You could leave them on the floor, melt them, sell them or maybe throw them at hostile monsters.

The main reason I created this RFE is however to make 'milkable' melee weapons less available.

'Milking' means triggering a spear/arrow-trap so spears/arrows are generated or purposefully retreating while a non-player character shoots/throws weapons/missiles at the PC, thus having plenty weapons generated.

N0t that I have a pony in this race, but there is nothing wrong with milking weapons. I don't see this as a good idea, nor is there really any difference in-game (you can throw those spears if you wanted to, and some people do)