I used the term "copycat" because I doubt that there's a central headquarters or leadership in BlackLivesMatter handing out orders to carry out terrorist attacks in the way that (for example) Al Quaeda operations were run when Bin Laden was alive. You're right of course that they are united by a common ideology, so it's probably best to refer to them as independent BlackLivesMatter terrorist cells (following one another's example) rather than copycats.
Didn’t mean to offend. Just that they deserve harsher term.
FRiend.