People seem to have made the same mistake that Stephen Colbert viewers did, when people freaked out "oh my God! He said 'Ching-Chong Ding-Dong'! Obviously he's bigoted against Chinese people!"
I won't link to the million diaries screaming at the dead people, while France is still mourning. But I think that even if they were completely racist, it would not be appropriate to do that.
It seems, though, that people aren't aware even of the fact that Charlie Hebdo is a leftist paper, and not a right-wing one. They were constituted specifically to go AGAINST the right wing, as their editorial mission. Charb, in this interview, approvingly notes that "Charlie Hebdo is the child of May ’68, of the spirit of freedom and insolence… " referring to the leftist student revolts of the hippie era in France then. Hardly something any right-wing raver would invoke. Nor would they say "myself, I am communist," as he says here. Plainly, then, he came from a communist and 60s counterculture tradition, which included atheism and a rejection of establishment power.