Some cultures are just wrong. The Islamists who believe people should be killed for drawing cartoons have a culture just as bad as that of the antebellum slave traders (interesting how the only culture that STILL has slavery nowadays is muslim...) or female circumcisionists in Africa.
Keep reposting the cartoons.
And while you're at it, keep posting the depictions of Muhammad that the Muslims produced in their art back in their medieval "golden era"!