> I just drew Mohammed on a napkin. Do you think I should pay a fine, go to jail, something?...
You know that's not what I mean :) and it's unrelated. Also your definition of blame is fallacious because punishment does not always take the form of jail/fine (i.e. social blame, personal blame).
Besides your action is not inciting; who will see it? If you now go into the town centre and happen to post it near a mosque athat has potential to be inciting. And you need to consider whether that is the sensible thing to do.
(the answer is; it's probably fine because no one is likely to get killed)
> then tell me how can I know, prior to expressing my thoughts, if my work will result in a murder.
Strawman; there is ample precedent for media, particularly cartoons, to cause offence and elicit extremist response.
> You're being vague if you say "some people, long history, napkim is okay, cartoon in national newspaper is not". I want to be a law abiding citizen. Should the government publish a list of prohibited things to say?
Deliberately so; it's a personal choice, not something anyone else should decide!
> I don't think you've thought this one through.
You skirt around some good points - particularly with regards to "social interference" (i.e. a moral brigade deciding what is right/wrong to publish based on their feeling on what will cause extremist response). However I think you make a few fatal mistakes in rhetoric (mostly by building on increasingly shaking links); ultimately I'm not sure you've thought the counter argument through clearly.