The Booster is all about PvP. Noone can deny that. And since neutral people are... well neutral I don't suppose they can build towers and claim land? That would not be neutral.
In a real war there's almost always one of the parts saying: If You are not with us, You are against us. That goes double for AO since Boss Ross already stated that neutrals are under Omni rule. And now that the Tir accord has fallen, Omni probably won't even acknowledge people's right to be clan. Story wise, is it reasonable to think that it's possible to be neutral in that world?