- It lays credence to that point of view ("why would the government censor it if didn't have some truth to it?") - It undermines the importance of having discussions about challenging issues - It makes those who hold the aforementioned views even more sure that they are correct, and that someone is unjustly out to get them
let people freely discuss these issues and we will all come out on top
Personally, I agree with zorse. One of the best ways to combat extremism is to give extremist groups enough rope to hang themselves. Nail them when they actually solicit or request specific illegal actions (calling for hits on people, calling for somebodies home or business to be vandalized, etc) but otherwise allow them to make fools of themselves in public. See how the WBC or the KKK marginalize themselves in the US by being permitted to publicly say what they think.
Radical Islam does not seem to be a sizable threat in the US (because of, or despite of, the US's loose hate speech laws... you decide) and domestic "homegrown" terrorism is a wildly overblown threat. People like "sovereign citizen" are widely mocked using material that they upload to social media. Would sovereign citizens still be widely recognized as nutters if they were not allowed to upload youtube videos of them making fools of themselves? Despite (or because of) the US's lax speech laws, we don't have a Golden Dawn equivalent political party that is actually winning elections.
Moreover, lets say that there is a person with a particularly sophisticated hatred of Jews, Muslims, gays or whoever. In fact, so sophisticated that its hard for you or I to counter his argument. This would be a fantastic situation! Why? Because we would either concede that his unfortunate views are correct, or seek a better understanding of the issue, perhaps by seeking someone who is an expert in philosophy, law or whatever and having a discussion/debate
In that circumstance we all win. You and I win because we have a more nuanced and sophisticated understanding of the issue, and everyone else wins because they can weigh the arguments themselves and make up their own minds.
If you're interested in freedom of speech, the Popehat law blog makes excellent reading. Ken White had an insightful post about this very issue earlier this year:
"In Europe, Tom Perkins might face official sanctions for saying the wrong thing about the Holocaust; here, he faces late-night jokes and insulting cartoons and the contempt of many. I like our way better." [1]
[1] http://www.popehat.com/2014/01/30/your-criticism-of-my-holoc...
Laws against anti-semitism lend credibility to proponents of conspiracy theories. "If what I am saying isn't true, they why is the government out to stop me from speaking about it?"
If you look at France in particular the attempt to shut down the comedic routine of dieudonne m'bala m'bala who has a routine that makes fun of the holocaust has likely done orders of magnitude more to stir up anti-semitic sentiment in France than his routine
regarding the anti-islam stuff, its a similar situation, with some important distinctions that I won't get into at the moment. Regardless, silencing anti-islamic sentiment, just as with silencing anti-Semitic sentiment, will only make the situation worse
P.s. its not just in Europe. In Canada we have 'human rights commissions' that can force you to apologize and pay enormous fines and legal fees for 'hate speech'.
1) you won't get hired in pretty much any company if they know.
2) you will be fired from the police force and/or army if caught having them.
3) government departments are regularly purged of much less controversial opinions.
4) If you talk about this in a cafe or some such someone will report you to the police who'll find a way to correct this.
5) some decisions you may make can be punished if you are known to have these opinions. Something like the human rights commissions example you gave.
If you're smart and have these opinions, you'll bury them deep down.
I find it funny how this works, and I truly wonder what European socialists are trying to achieve by making this happen. They've already succeeded in making the extreme right comparable in size to the moderate left, and far, far larger than extreme left. And they're driving more and more people away because most of their actions are really about jealousy-driven wrongful accusations within their own people. The right, even extreme right, is currently very open to dissenting opinions and cooperate with eachother even when there exist large rifts in ideology between factions. The cynic in me says that's because they have to be. But it's giving them power.
As to why they do this, having lived there, the answer is extremely obvious : because a big class of people enjoy doing this to other people. It shows they're a good person ... yes, really.