The McCain amendment bans "cruel, inhuman, or degrading" treatment of any prisoner by any agent of the United States. This could be interpreted to ban almost anything. The most important reason to defeat this is that any interrogation, even the most benign, will be hung up in legal maneuvers by those seeking the defeat of the US (among which I include Democrats).
I totally agree with that appraisal of the McCain Amendment.
This creature is the individual who gave us the McCain-Feingold Law. He is a fawning sycophant for the media and has little or no actual concern for America, our Constitution, or anything beyond advancing his own image in the eyes of the media.
Only a short time ago McCain pretty much walked on water and criticisms of him personally were poorly regarded in this forum.
His recent actions demonstrate beyond any question of a doubt not only his unsuitability for the Office of President, but his unworthiness for the office he currently holds.
Cataline comes to mind when I think of the man.
At any rate, the very valid criticisms you point out are adeqaute grounds for rejection of the McCain Amendment by COngress, or its veto by our President should the law cross his desk - an action past experience has shown would be most unlikely.