It's about the crackdown following the attack. There has been various cases of people supporting (or seen as supporting) what the terrorists did being fined or condemned to prison.
> I find France's own crackdown on non-protected free speech during and shortly after their legendary march for free speech to be much more ironic than a business obeying local law.
I think you misread which comment I was replying to. That was the grandparent of my comment, while the one I was disagreeing with was basically saying that it was hypocritical of Zuckerberg to obey local laws after saying "Je suis Charlie." I don't think the idea "People shouldn't be killed for what they say" is necessarily incompatible with following local laws about what a Web service may publish.