In a word: panic.
There are three main reasons why hatred of Russia is so important to them:
First, they “lost” Russia. December 26, 1991, the day the Soviet Empire dissolved, is their 9/11 or Pearl Harbor. Much hope had they placed in the ways of Lenin and Trotsky. The ramifications of subtle changes made by Stalin were only realized too late. Then, in the blink of an eye, their idyllic model was gone. For a while, they went into mourning. Now they are vengeful, feeling betrayed by Russia’s leaders and by her citizens.