Given that you have that impression, I understand why you reacted the way you did, but your impression is incorrect.
It's like saying that when I use a gun to defend my house from a burglar wearing a red hat, that my aim is to kill people with red hats. Completely missing the point.
The aim of this movement is to defend free speech (my house) from extremists (burglars) not people who happen to be muslim (wear red hats).
I might also add that the Swedish artist discussed now (Vilks), has a history of provocation in his work. Not only for muslims. He also made a cartoon of one of these, which imho clearly overshadows the Muhammed reference:
I would avoid saying "HN demands" anything, since this thread shows that people's views here are all over the map.
I think you're misinterpreting their intention. Rather than saying people don't have the right to be offended, they're saying people don't have the right to kill over the offense.
The point is that some things are more important than avoiding offending people (particularly, I might add, over something so ridiculous as drawing a picture).