You can't. But that won't stop some people from trying to. The only tiny spot of not so terribleness in this tragedy is that at least the murderer was a legal 'Catholic' white migrant rather an rejected asylum-seeker 'Muslim' arab.
There are plenty of people around who weren't. Ask any of them and they'll tell you about the hooliganism, violence and police indifference that were rife in those days. Poland is much more civil now. That doesn't sound right to those who have the "Poland is going to hell in a handcart" attitude, but it happens to be true.
Unfortunately quite a few of the Poles here in the UK at the moment really are the scum of society.The earlier wave who came in 2004 were far better people. How would Poland like a load of uneducated, barely employable Brit drunks & thieves to pour over there and make themselves at home? Things will only get worse once the UK minimum wage increases to £9 per hour and even more undesirables arrive here....
This event is just another proof that Poles becoming nervous. i understand them. Too much pressure and machinations around them. First Poles that would flip are usually those who are anyway little bit crazy. But, rest of Poles are also increasingly nervous.