BigGuyCIA
Yer fond of me Lobster!
Who is Earth and who is the Batarians in that?
The territory was set aside for the Batarians before the Citadel Council let the humans claim it.
Because they're assholes.
I dug into the actual history of what happened.
Order of events (some paraphrasing):
Batarians first contact with the Citadel Council -> Batarian Hegemony aggressively colonizes Asari planet, bombards Salarian colonies, and skirmishes with Citadel Council forces -> Humans come into the picture and settle planets in no man's space -> Batarians request the council tell the humans to go away -> Council says "lmao fuck you Batarians" -> War -> Batarians lose and scurry back into their own space.
In short, Batarians were and always have been complete assholes from the get-go, and everything that happened to them was largely deserved.