In Germany, it would be a question of the context.

As a cartoon accompanying an article critical of a faith it would be considered as free speech.
Someone wearing the T-shirt at a concert of the band would be considered free speech.
Someone wearing the T-shirt walking down just any street would probably still considered using his right of free speech.

Someone wearing that T-shirt ostentatively during a Christian religious procession or in a church would probably be sentenced.
Someone walking with that T-shirt in Bunnahabhain's version down a street with nearly exclusively Muslim neighbourhood would be sentenced for inciting religous hatred.

Wolfgang