frum thinks it is an important freedom. http://www.thedailybeast.com/articles/2012/09/19/the-cost-of-cartooning.html
for myself, i think the freedom to insult is not quite as important as the freedom to disagree without insulting. but legally speaking, drawing bright lines between these two things is impossible even if it were desirable.
i have no idea why some folks want to belittle moslems/islam, any more than i have any idea why folks once thought it was okay to make jokes about black people or "the retarded". one avoids doing so because it isn't polite, and also, in fact, because it is not terrifically witty to poke fun at people who are sensitive and/or vulnerable. in addition, the folks drawing the cartoons aren't the ones facing all of the consequences of doing so.
i am not a moslem. a religion of submission is not my thing at all. but are there things within islam that i, a non-believer, can learn from? yes. i think it is worth thinking about how we find value in this relationship. rather than having it be a weeping sore which we repeatedly poke.