I'm a lot more willing to defend the Charlie Hebdo cartoons than say the Innocence of Muslims film. We're talking about a satirical magazine that was firebombed last year for releasing an edition that was 'guest edited by Mohammed'. Sure, the latest cartoons are ill-advised and poorly timed, but this is a magazine that pokes fun at everything and I can appreciate them not wanting to back down.
The difference is that they arent just spewing hate, it's satire and the people being offended by it have to go out of their way to do so considering they have to go out and buy something that they're clearly going to disagree with.
It's the same reason I'll go out of my way to defend South Park. You get hilarious hypocrisy like Isaac Hayes quitting (because it's fine to poke fun at everything else, but when it's his religion they've gone too far.).
Basically I only have a problem when things are put out there that serve no purpose other than to offend and antagonise people.