Well your first mistake there is accusing Charlie Hebdo of racism: Islam is a relgion not a race and there are Muslims of every race and nationality.
And because it is a religion, not a race, it is open to questioning, satire and maybe ever some "hatred" like all concious choices. You don't choose your skin colour, sexual orientation or to have have any disabilities and so these topics should not be satirsed - but concious choices like your political affiliation, the football team you support, whether you use Vi or Emac and your religion are open to scrutinity and satire.
Also - have you seen any of the cartoons they published? The vast majority are not insulting to Mohammad and are mostly poking fun at those who think it's ok to warp his teachings to the levels that it's ok to murder 16 innocent people who drew something on a piece of paper. (How weak must their faith be if a cartoon can hurt them so?)