The Left and Right should both have a problem with this.
First of all, a government should not have the power to ban a belief, no matter how vile it is. Anyone should have the right to believe what they want- it is how they apply that belief, if it infringes on some else's rights, then that application or action of the belief is what should be addressed, not having a belief.
Second, well, I shouldn't have to mention the problem one should have with banning books- no matter how much you disagree or dangerous it may be. As we've seen through history, the most dangerous book is the one that is banned, because then you give it even more power- the power against authority.
Wilders, like LePen and Farage should be a clear reflection of the difference between the political right in the EU and US. They are very distinct in many ways even if they cross over on some issues..