Copycat usually infers a mentally unstable person repeating the acts of a notorious felon.
These are men who believe the same thing and carrying out murders. That’s any army or terrorist group, or both.
Not to me a copycat.
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.
You are absolutely correct. Like minded, not a copycat. This is killing for a “cause” not for the thrill of killing, even though these thugs may indeed be thrilled by their killings.
The proper word is “rebellion”.
And it would behoove us to ponder carefully the question of what they are rebelling against.
Agreed.