Well I'm the fly in the ointment.
The President has what authority has been granted him under law and within the boundaries of the Constitution. He has rights and powers, however I find no reason they ought to be unlimited or unquestioned. We had this happen with Bush who decided that his Constitutional position allowed him to effectively veto habeas corpus.
Here's the Constitution on the matter.
This limited ability is given to Congress, not the executive branch, nevertheless at least one american citizen on US soil was detained without due process. I found that disturbing.
In the case of Obama he has certain powers as you say, however I am not sure his saying something is so quite good enough. I do not believe that there was ever an intent to remove all accountability or transparency in any process tantamount to assassination of a US citizen. Given the level of "oversight" which turned out to be lip service, the credibility of the Presidency has rightly been called into question as we were mislead on some issues.
In the end it may be that there is an unfortunate need to do what is contemplated, but there has been no allegation of immediate threat, nor evidence a plot being aided by this contemptible person that is in anyway subject to independent scrutiny that I am aware of.
Group association, however despicable in itself, does not seem to warrant summary execution without true need, and I submit that there is little reason to trust the unverified.
This needs to be addressed. Do you think that would ever be allowed