You say it is about being exceptionally offensive but was it really?
I'm glad you mentioned being from Liverpool, there was a film called 'Hillsborough' that referred to the most offensive headline.
We had the drama 'Anne' and there have been numerous books and lectures, Phil Scraton being responsible for one book and for giving a number of lectures about the tragedy and the continuing tragedy of the aftermath.
In those lectures headlines are shown as are photographs of the crush.
They are part of the 'story', take them out of context and they are incredibly offensive.
We don't know the actual resource that was used.
Were they the Charlie Hebdo images? Were they the Danish images? Were they the ones created by a Muslim and added to the Danish images? Was it the pic from the 'pig squealing competition' that an Iman claimed was published?
Some Muslims are offended by any depiction of Mohammed, but the images are not actually banned in the Quran.
Images of Mohammed appear often in Persian works of art.
Some Muslims believe no living thing should be depicted in drawings.