Organise a "draw Jesus sodomizing Mary" contest in Texas and you'll get crazy Christian jihadists doing the same thing. If you set up an event specifically designed to insult/offend/antagonise a particular religion, you're always going to get a response like this from someone.
Highly unlikely. While such a depiction would horrify a good many xtians, there is no explicit commandment to kill anyone making such a depiction. There is certainly no group of clergymen suggesting that anyone take such action. Not that there hasn't been such madness, on the part of xtians, in the past, but western society has largely recovered from that level of insanity.