It is not a giant leap of thought where milkshakes could easily become bleach or HCL acid. To that end, if someone throws something like that on you, you should reasonably assume you are being mortally attacked and defend yourself accordingly. This includes those SJW’s going around throwing bleach on men who are mansplaining.
In short, you throw something at someone because of a disagreement, be prepared for the dire consequences.
“Leftists have lately thrown milkshakes at various right-wingers in England and in the past few days have splattered their first member of the U.S. Congress with one”
maybe we should limit milkshakes to a 7 oz. magazine.