The implication, or maybe the intsruction, is that British people should care more about the lives of other British people, that they don't know, rather than the lives of Lebanese people that they don't know. Why? The degree of caring about someone else's life based on nationality is sickening.
Also, there are/were 20,000 British people in Lebanon. I wouldn't have thought that Lebanon was a prime destination for emigration for British people, so what were they doing there? Most were business people making money out of the local people. They went to Lebanon to exploit. The Lebanese people have no choice but to stay due to the immigration restrictions of other countries; the British, and other Europeans, chose to go there. Surely, the Lebanese should be evacuated first.