I notice that “judenmord” is one word. I know German is full of examples of this. In English, when we concatenate two words, it tends to differentiate the idea from other ideas, so “jewmurder” would imply a fundamentally different concept than “murder”. Is this the same in German? Does the concatenation imply a seperate concept from “murder”?
No. "Massenmord" is mass murder, etc. They just like to concatenate words.