Yes both are an assualt, but chew is abhorant and disgusting.
He could have spit on the book and accomplished a similar purpose.
Would you rather they say "when the left throws blood on a fur coat"?
It is all in the same league. "Pie in the face" is not funny when you consider all of the contaminents put into food deliberately every day. It is all the same offense.
People get bent out of shape over "white powder" being sent through the mail. At least the origins of this fluid were known.
Every VietNam Vet has had a dream to spit in her face, including my deceased husband, who was a VN vet. She deserves every bit of spittle she gets.