You are correct.
That said do you really think people who are against police assassinations are out trolling, flying a false flag, saying that the cops deserved to die?
They are showing the true, ugly face of liberalism.
Not likely. But I’ve seen plenty of claims that over the top or extremist conservative sentiments must be posted by ringers.
The No True Scotsman fallacy never dies.
In actual fact, any political position will have its nutjob supporters. The relevant position is of course whether the “normal” people in that group don’t say similar things because they don’t believe them or because they think doing so would be inadvisable.