I do beg to defer here, slightly. IMO what these men do are worse for the reputation of Islam than the movie.
The movie and cartoons were produced by Islamphobics and haters so no one can really take them to be anything of concrete proof against Islam. But what these men are did claiming to be Muslims and quoting Quranic ayahs will be assumed by many to be Islam!
The Prophet himself whilst patient with disbelievers in Islam abusing him, showed great animosity towards deviants and extremists,because the latter can do far more harm by claiming what they do is drawing them closer to Allah.
Hence yes, I believe all Muslims should condemn strongly the actions of the woolwich killers!