You may protest that this is a false equivalency, that the above-mentioned things are different from Christianity, which is merely belief. But that would simply be picking and choosing what you personally feel is open to ridicule - what's left is, by definition, sacred.
You may say, "I'm secure in my beliefs - go ahead and mock." Well, to be honest, we'd be in the same boat, you and I. As a Christian, I suppose I wouldn't mind watching "Life of Brian".
But to put ourselves in the shoes of the protesters - would you want the next generation to grow up in an environment where, say, the science of evolution is the target of mockery? (I imagine in some parts of the US that's not so far from the truth.) My point is, laughter is a powerful weapon. And children laughing along at the jokes may not catch all of the nuance outlined in the BBC article. Even if nothing is sacred, some things may still be important enough to try to influence the culture over.
Were the protests silly? Did they end up achieving the opposite of what they intended? Sure. But that's a matter of results, not purpose.
Maybe we should all learn to think twice before we laugh.