Because it is the prime example of where 200 years ago people of one culture dominated the country, and then immigration started. The Jewish people (with a different culture) then immigrated up to the point they had the majority, and started to discriminate against the indigenous population. Europe felt bad about what happened in WW2, and gave them additional powers (which they exceeded, by eg not following what the UN told them to do). They now split the country, but still keep control and attack whenever they feel like it.
It is OK to attack a country when its government sanctioned an attack on your country. It is not OK to attack a country if a few people killed some of yours. That is an attack on the mainly innocent population, just as the riots in london were an attack on the innocent (whatever you might argue the riot was against, the shopkeepers were not responsible).
Unless it is a sanctioned, government organized attack, you cannot hold the country responsible. The lack of differentiation between who is responsible between people from a certain racial background amounts to nothing less than pure discrimination. That is no worse than shooting a few Jews because a Jew did something wrong, like Nazis did before putting them all in concentration camps.