Satirising and mocking the very real and recent victims of a terrorist attack is just as insensitive, crass and disgusting to normal functioning humans as drawing a stickman cartoon of a fictional guy from 1400 years ago to 1.5Billion lunatics.
I know this is hard to comprehend for many and understandably so. If you find yourself supporting the hebdo cartoons and then renouncing that support over these russian drawings, maybe it is the content you are supporting / not supporting and not freedom of expression.
That said, there is a funny irony here that im sure has gone straight over the 1.5b lunatics heads in that a publication that they cried and cried and cried was "Islamophobic" is choosing to mock the 224 innocent victims of an Islamist attack