What? Just destroy all those Orcs, those potential servants, those warriors? No, no, no.
[x] Kill Azog
-[X] Demand that the Orcs serve you now.
--[X] Kill any that refuse.
---[X] Repeat until all the Orcs left have sworn themselves to you.
Waste not, want not. Never throw away potential resources.
They are broken tools. There are better orcs in Gundabad.