The decision to mine it and the efforts Gallywix went through to keep it hidden from the Alliance is the reason why diplomacy wasn't an option as soon as the Horde started extracting Azerite. Most of the Horde didn't even know about this actually. To outside observers it is clear the Horde wanted to keep this hidden.
The point I'm making is that, if somebody better was in position of warchief, they could've put a halt to it and informed the appropriate orders and figures. This way it was a clear power grab and naturally the Alliance dives into the power grab themselves to avoid being outmanouvered.
What's worse is that the entirety of the Horde suffers setbacks because the greedy goblin greeded the undead high elf out.