That’s exactly what it is!
They are the only people with the motives and more importantly the time to engage in such political theater.
Which group do you think it is?
They’re physically fit which implies they’re young people. That makes me think students, interns, rambunctous young leftists with a flair for theatrics and “direct action”, maybe Antifa. Seems a little too far out to be the feds, but who knows.