Shades of Hitler

I read this today and felt a familiar chill -

'Police have launched an investigation after a pig's head was left outside a community centre being used as a Muslim place of worship.'

I remember 1930s and the time before WW2, when I was a child,  and Mosley and the fascists in London were doing excactly the same thing to synagogues.
Why are some people so filled with hatred? In this case they blame one section of a community for the evils carried out by the few and then go out of their way to offend everyone.
Their knowledge of British history seems to be sadly lacking. For God's sake - go out into the world and do something useful for a change. Why make trouble in a world already filled with so much hatred and trouble.