Victoria comments as well (and comments very well indeed).
Searching about using tools like Tailrank, Technorati and Google Blogsearch it would seem that the political response to this has been almost exclusively from the right of center blogs.
The consensus from opera and culture blogs (as exemplified by New Criterion editor Roger Kimball) would seem to be that the director of this opera, Hans Neuenfels, is an idiot. He has been hacking away at classic operas for years, and if he were to be figuratively beheaded as to never be allowed to commit his churlish and asinine productions ever again, that wouldn't be a bad thing (please note that I said figurative)
It should be noted that this production premiered in 2003 and presumably went off without leading to actual beheadings.
I think Prof. Althouse's take on the matter is worth noting, too
This is a complex problem. Neuenfels's production takes the easy faux-daring route of "Piss Christ" and the Madonna crucifixion, but at least he had the nerve to hit all religions equality, and not to single out one religion. Perhaps he did that because it wouldn't have made any sense to go after the conventional target of Christianity when it's an opera about the Trojan War. It doesn't make all that much sense to drag Buddha, Jesus, and Muhammad into that setting either, but bringing them all in to join their super best friend Poseidon made some kind of crazy sense.
Now that some Muslims have made it painfully obvious that religion-taunting is not an easy game anymore, abandoning it expresses fear, not respect for religion. And continuing to disrespect the religions that don't lash back only highlights that cowardice. Poor transgressive rebel artists! How are they to shock the middle class anymore?
I searched long and hard for an actual liberal site that mentioned this and found this bit of wisdom from Mahablog
Today there’s some grumbling on the blogosphere about “political correctness” and how “artistic freedom” is being sacrificed to placate Muslims. To which I say, try performing this critter in the Bible Belt. As soon as the Holy Rollers hear about Jesus’s severed head the opera house is as good as vandalized, if not torched. And every Mozart CD in Alabama — all six of ‘em — would be tossed on a bonfire, along with video cassettes and DVDs of “Amadeus.”
Crazed Islamo-Fascists intent on killing or converting all unlike themselves aren't the problem, it's those Christians who are ruining the world.