"What would we call a person who cannot differentiate between right and wrong?"
"Can not" and "Will not" are the operative terms we must emphasize to look for when figuring out which word to use in this situation.
A Sociopath is one to whom "morality" does not exist, a "can't" person. This stresses the INABILITY of someone to sort actions into two empirical categories, right and wrong; To this person the very concept of right and wrong does not exist.
(Amoral- "I CAN do no wrong, for I do NOT know what it is." -Satan in The Adventures of Mark Twain)
Contrast this with:
Psychopath, one who actively does things they know are wrong
(Immoral- "I don't care, I'm doing it anyway."),
OR they believe that they exhibit or create the standard of morality.
(Trans-moral is a term that I have sort-of coined, or co-opted- "If I am doing it, then it must not be wrong.") At it's core, this implies acknowledgement that morality exists and that it has a standard, and actively doing something contrary to that standard, motives aside.
[ in rebuttal to @Baiwr ]
The terms must always be relative to the intent and the socio-cultural milieu of the one being described, to wit:
If a person has been raised steeped in propoganda in North Korea, then it would not be abnormal to justify anything The Great Leader says or does. Because how can you refute god?
If you were the child of Kim Jong-Il, or go, according to every single person you will interact with during your formative years believes to be true, and you were told that when you become The Great Leader that you are also god, then your brain will add this to a long list of other memes (I use the word in it's original context as a unit of information, not it's connotative definition as a unit of lolcats on teh intArwebz), and you will conclude that whatever you do is right, you can do no wrong because how can god do wrong?
To move on to the second topic of my answer:
The answer to the question OP poses will not properly fit into the sentence they have provided.(Oh how I do tread grammatical grey areas such as my choice of gender-neutral singular pronoun)
That, in reality, is two questions, the second implied question being:
"How or with what word would one describe a person, persons, a people, or peoples who believe that the leader of a country in which they may or may not actually reside or hold citizenship is qualified or (time to coin yet another new word) supra-qualified to govern and/or is considered to be morally or personally equivalent or superior to themselves, as stated from the viewpoint of one who believes such to be false at best or totally antithetical at worst, and done in a condescendingly euphemistic pejorative or in a way in which the connotation of the descriptor is condescending or is used in similarly condescendingly occlusive implications, such as tone or body language."
I'm sorry but your example sentence is so vastly inappropriate (in gramatical terms, I make no statement as to my or your beliefs) that I am purposefully expounding on the difference between the question you asked and the question I can infer you meant to ask and now why it is inappropriate with as much hyperbole as I can muster, while at the same time absolutely intentionally not giving you a word that I know that is the word you are seeking, which is merely implied between the non-sequitur of your stated question in order to make a point. (If I'm being too anal or harsh, I appologize, but I do assume that this particular English Q&A website is held to much higher standards than other English topical discussion boards or sites.)
My pointless exposition on a topic that is nearly a year old already (and will most likely never be read by OP) is complete.