Really?
I am not aware of any abortion protester killing anyone, at least not while in that guise.
Can you provide a citation?
You’re kidding right?
Let’s use the Tiller killer as an example.
He was a member of Operation Rescue and had their number on a post-it on the dash of his car. He has probably donated money to them (we’ll see) but it has already been shown that he was a member of OR. Was this an officially approved OR action? Of course not - they have more sense than that. Was he an abortion protestor? Good luck finding a jury of people that won’t believe that he was an abortion protestor whether or not he was wearing that hat at the moment he pulled a trigger.
I suppose you could argue he wasn’t at a protest or waving a picket sign at the moment of the murder and therefor he wasn’t a protestor but that strains common usage of the English language quite a bit.
Most people will say “an abortion protestor killed an abortion doctor” (or something like that) and know what is meant.