We've been talking about "the cover" - the reason cited for the attack was "disrespecting the prophet" and the like. It wasn't one particular cartoon, AFAIK, though I haven't checked carefully...
Charlie Hebdo apparently republished the Dutch cartoons in
2006 and the firebombing was in 2011. They've been a target of the violent kooks for a long time.
12 people died there because they were shot-up by deranged gunmen who used religion as a reason. We shouldn't necessarily take their proclaimations as the truth, though. Perhaps they are looking for ratcheting up of laws against Muslims in France and the EU that they can point to as "western attacks on Islam" and thereby increase recruitment. Thus feeding into their desire to make this a religious conflict will help their aims....
The post-attack cover was certainly newsworthy, but I don't see not publishing it as being cowardly or selling out or something. There were were reasonable reasons not to, and it was easily available elsewhere. I doubt that the NY Times's traffic changed much as a result of their reporting.
FWIW.
Cheers,
Scott.