You do not decide what is blasphemy to people not in your religion. If Islam says depictions of their prophet cannot be shown and they want to honor that, fine. But people cannot demand others not of their religion comply with their beliefs because they do not believe in them.
This is the central disconnect of people like Anjem Choudary, a radical Muslim cleric who believes freedom of speech doesn’t extend to insulting Mohammed and spoke of the “consequences” of the Charlie Hebdo cartoons that they just refuse to recognize.
We do not live in an Islamic state. Better yet, the majority of people in Britain and France are not muslim, they are christians or agnostic. In America, like 1% of the population is Islamic. We do not care what they think is a sin anymore than they do with what Catholics think is a sin. Some idiot in Florida burns their holy book and they riot in Afghanistan. What rational person would care? Because they have absolutely no tolerance for anyone who does not share their faith. We do not want to share it and never will. They are the ones that have to get over that.
If they cannot recognize that Western values are different than their own, that is not our problem, its theirs. By wanting non-islamic people to not show their prophet, they are de facto trying to force us to recognize Mohamed was a prophet and believe what they believe. Its not insulting to them, it is to us to try to impose your religion on places that do not want it. If this guy wants to live in a place where no one is allowed to insult their prophet, move! Go!
There are many countries that share that belief, you are not in one of them.