Depends what you think their point is. If you think their point is that the cartoons upset them, sure, they already made their point. If, however, you think their real point is something else, such as that they are willing to commit violence in order to force us to capitulate to whatever their demands are, and that we are too weak and cowardly to stop them, then no, they're not done making that point. They'll keep trying to make that point for a VERY long time.
Until something makes them stop, yes, they will continue to do exactly that.
Yes.
And since you brought up icebergs, I'd like to mention a little historic parallel, namely the Titanic. When it spotted the iceberg in its path, it tried to turn to the side to avoid it, but couldn't do so fast enough. So it struck a glancing blow which tore a small gash down much of the length of the hull. The ship was designed to withstand flooding in several compartments, but the gash tore through one too many, and the ship was doomed. Ironically, had the Titanic instead decided to hit the iceberg head-on, it might have survived. The front compartment would have been badly damaged and would have flooded very quickly, but flooding probably would not have extended any farther back into the hull and the ship would have remained afloat.
Relevance to the current dangers? It's too late in the day to avoid danger. We must take the problem head-on. Some hardship and conflict up front can save us a whole lot of grief in the long run.
Scrutinizer is partly correct. We need to stand ready to kill such people, and we must display our strength and conviction in that regard quite brazenly. But if we're successful at doing that, we won't have to do too much actual killing.