If we apply your reasoning to another scenario you are saying that you think that it would be perfectly legitimate for a coalition of Muslim states to invade Israel and divide it up amongst them. The people who cite historical examples predating the ban on acquisition of territory through force or their own made up rule of "they attacked first" are not much better. Do some actual studying of international law so you know what you're talking about, or if you can't do that at least use your common sense and realize that a legalized free-for-all land-grab does not work.
Four Libyan soldiers said killed in battle with Islamists in Benghazi (Reuters)
from the article: Israel treats 7 wounded Syrians who approached Golan border