Did the kapo hire a false flag?
I doubt that this was a false flag attack. Soros does not need (and would not get) much sympathy from any attack. He has too many real enemies and this sort of thing makes him look weaker.
I am surprised that this incident was allowed to get any publicity at all.
I expect this will be wrapped up very quickly with arrests of "members of a right-wing militia group" - that turns out to be 30% FBI informants. I would not be at all surprised if the bomb was supplied by one of those informants and was designed to be a dud.