A useful tool when evaluating a claim for freedom of speech is to invert it. For example, replace "Muslim" by "Jew", and decide then if an argument in that form would be acceptable. I haven't read the article; the BBC news article seems a little more balanced than the CBC one; it also points out that Maclean's refused to publish a response.

Freedom of speech is important; to allow only one side to present the case is not promoting it, and when the medium in question has overwhelming coverage, the failure to present one point of view amounts to support for the other.

There are of course times when a group or individual is so far beyond the pale as to have lost their right to this freedom; no one would support such freedom being extended to extreme racists*, holocaust revisionists who lack overwhelming new evidence**, violent dogmatists** etc. I can't see that mainstream Islam comes into any of these categories.

* including of course antisemites
**i.e. all of them so far
***like al Qaeda and the Clontarf branch of CCE