Individuals are the best actors to determine for themselves what causes they are willing to make sacrifices for. This is why we allow individuals to volunteer for wars they believe are just, to serve as humanitarian aid workers in impoverished countries, or for any number of unpleasant and potentially dangerous things. If they wanted to, no one can tell the editors and cartoonists that they were wrong to take the actions they did on account of personal safety.  But anyway, it is clear that they did not comprehend the scale of the risk they were running by publishing the cartoons, so they cannot be blamed for bringing this upon themselves.