My copy hasn't arrived yet, but I can't resist joining the fray at this stage, and add a reference to something the book doesn't seem to mention.
I'll refer to an essay written by Renaud Camus , himself developing an idea by Alain Finkielkraut "L'Anti-racisme est le Communisme du XXIeme siecle"
(Anti-racism is the Communism of the twenty-first century).
The author's tenet is that people need ideologies and good causes to believe in, and when they turned away from Christianity in Europe, some still needed to believe, and turned to Communism.
Communism is an ideal about sharing. As Carly notes it turned to everybody having very little (though not nothing) but that's not the way it had been envisaged at first.
When it turned out to be a failure, people still needed to have a cause, and the author's thesis is that many turned to anti-racism.
Again an excellent cause: who could object to it?
At first it was all to the good, they did good work fighting racism, but now it sometimes feels like anti-racism is becoming an ideology in its own right at least in France).
Because of the moral prestige anti-racist organizations have, some of them seem to be enjoying a sense of power. It's not a power to do any real wrong, so this will never gain the negative influence of the previous ideology (marxism) but it's a power they sometimes use to prevent whoever is not one of them from speaking, or that they will use to ridicule whoever is not one of them and make him look like a pariah on the intellectual and moral scene.
For example, they sometimes condemn a writer using truncated quotations out of context, never bothering to read the book, and then will stage loud demonstrations outside the room where this writer is going to give a talk about, say, education.
Also, some anti-racists can feel tempted to use the respect and admiration their cause has got them to help a "cause" that was underlying their anti-racist fight: one of those organizations in France, the MRAP, supports Islam -- at one stage they had to get rid of one of their leaders when he openly used anti-semitic rhetoric, so he left, but the pro-islam bias, which should not be the aim of an anti-racist association, has remained.