What goes round, comes around
Unfortunately for all of us, this sort of attacks against both military and civilian infrastructure has been effectively legitimized a while ago. If it is (il)legitimate [1] for the US to hit Iran's centrifuges or air-defence network with a destructive virus, it is equally (il)legitimate[1] for Iran to hit defence and government installations in the US. If it is (il)legimate [1] for the US to booby-trap Russian civilian energy infrastructure, it is equally (il)legitimate [1] for Russia to do the same to the US. And on and on it goes.
Unlike the convenventional warfare, it is the more technologically advanced opponent, which presents a bigger target, who ends up at a greater risk and a greater disadvantage. It is inconceivable to me that this point escapes american military and civilian leaders - and yet it is the US which continues to enthusiastically push "cyber warfare". I'd really love to understand what logic and what compulsion drive them.
[1] Feel free to choose the word according to taste.