Actually you have the right to say that...and I would defend your right.
I also tend to require all the legal requirements for US citizens to be murdered by the government.
As far as Goebbels is concerned if he was collateral damage fine. If we had been going after him in particular to murder him as a citizen...no. He would have been captured and brought before either a court or military tribunal.
If a US citizen joins a wartime enemy army in uniform there is no question of our moral and legal right to kill the bastard. The real comparisons are:
(1) if this guy had been in Saddam’s army or the Taliban’s army fighting us from within a recognized military unit, it would not matter a bit (legally or morally) that he was a “US citizen” when he was killed. The only relevant status is what he was doing to wage war as an enemy combatant against the USA and our people.
(2) so the only relevant difference is that this guy helps to run violent jihad campaigns from remote places in Yemen (until now, when he is toasted). Being a US citizen should provide no protection whatsoever in such circumstances.
This is not at all like a case in which someone could be captured domestically, when various civilian legal issues might arise. He was an “enemy combatant” fighting us from beyond the reach of civilian authorities. This is an easy case not a hard call. The jihadists one can debate about are the ones who can be captured by domestic police and FBI.