Why isn't it stuxnet?
This time it would make perfect sense if it were the US's own security forces. Their job is to protect US security, and probing vulnerabilities of critical infrastructure is surely part of that job.
So, if it falls short of a stuxnet (OK, perhaps stuxnet-with-dummy-payload), does that mean they're not doing their job? Or just that attacks are being reported selectively?
Coincidentally, some of those same security forces are well-known for framing foreign powers.