Why does it matter which side sent the fake bombs?
Under normal circumstances I might agree with this analysis. But we're looking at a political environment where, during the last election, we had literal riots on the streets instigated by one side, and government officials abusing intelligence and surveillance authority to influence the election. When those riots and abuses failed to win the election, the same side moved immediately to institute a coup by any means they could come up with, and failed again. Their tactics then shifted to more riots, another coup attempt in the form of a special counsel, resistance by government employees to duly elected officials exercising their ordinary legal authority, and then to literal mobs hounding their political opponents in restaurants, in elevators, even in their homes. And now, when all of the above appear to have failed and the GOP's Jobs Not Mobs message appears to be resonating, we have a veritable flood of fake attacks on left-wing political figures and financiers.
The key word there is fake.
Someone who was nuts wouldn't put together fake bombs. They would put together real ones. Maybe they wouldn't work as intended, but they would be real, and they would be intended to harm.
These? They were fake, they were intended to be discovered and publicized, and they were deliberately harmless. That makes them the product of a political actor seeking a political impact, not a lunatic trying to harm people because his brain doesn't work correctly.
That doesn't mean he's necessarily completely rational, but he's rational enough for this to be a political stunt rather than an actual murder attempt.