This isn't really showing unity thought. The threats are non-credible but you are giving them credence. It does feel a lot like a fearful reaction. And very little to do with unity - because the chosen symbol alienates Muslims from the protest.
Think of it this way; if someon blogged random death threats because of a cartoon of George w bush would weaigh and ignore it? Why the double standard here then?
There is no credible threat, but some appear afraid enough to see it as one.