The word "actor" has meanings other than "thespian".
Namely, it's a person responsible for an implied action.
Now, I'm well familiar with the history of COINTELPRO, and have zero doubt the same sort of stuff happens today, but this doesn't have the trappings of a false flag operation.
Mainly because there is no political ideology associated with the attacks. The history of false flag operations is much more one of discrediting "dangerous" political groups (like the Black Panthers), and much less one of a general "create terror and watch people turn to the state." Even if the latter is a goal, why not take advantage of an opportunity to discredit anti-statist groups while you're at it?
Not to mention that the assets used by false flag operations are usually marks, and they almost always die (or go to prison) for real. They aren't actors – they're just marks.
That said, terror always benefits the state. But the state need not always act to achieve this end. There are bad people out there, and government is not capable of stopping them. In this sense government is a self-fulfilling prophecy: "Well, we need to exist to keep you safe. And, oh, look over there, a psycho! See how much you need us?"
The big lie is that government is capable of preventing, or even meaningfully reducing the likelihood, of such attacks. You don't need conspiracy theories to fight that lie. It's a lie, regardless of whether government is angelic or sinister.