This is partially correct and partially wrong. Normal humans do understand the basics of right from wrong without people teaching them, but that understanding is not necessary to hold them responsible for their actions. It's fairly clear that psychopaths do not innately understand that the horrible things that they do are morally wrong. In fact, a characteristic of psychopaths is that they treat moral issues as if the were issues of convention. In other words, they have to be taught that hurting and killing other people is wrong and, when they do, they treat it with the same moral weight that a person might treat a prohibition against chewing food with their mouth open, something that you can get in trouble for not doing but not something that you might consider doing if you think you can get away with it.
Despite all of that, people who are told this about psychopaths have no trouble holding them morally responsible for their behavior and, further, had no trouble identifying them and their behavior as evil. This is one of those example where the rational analysis of morality, which demands that people know they are doing wrong to be held responsible for it, bears no resemblance to the moral thinking of real people who do hold such people responsible for their behavior and do consider it evil.
Exceptions do not prove the rule...you know that Doc.
It's also fairly clear that the rest of the animal kingdom doesn't understand the concept of God, but you can't demonstrate something that can only be known to them.
What if there were a third element between the observer and the psychopath, that does not lend itself to rational inquiry, yet is causal to the behavior being observed.
You said that you weren't a fundamentalist or a literalist, but you seem to be familiar with the Bible.
Here's Matthew 16:21-23:
21From that time forth began Jesus to shew unto his disciples, how that he must go unto Jerusalem, and suffer many things of the elders and chief priests and scribes, and be killed, and be raised again the third day.
22Then Peter took him, and began to rebuke him, saying, Be it far from thee, Lord: this shall not be unto thee.
23But he turned, and said unto Peter, Get thee behind me, Satan: thou art an offence unto me: for thou savourest not the things that be of God, but those that be of men.
When Christ said "Get thee behind me, Satan," he was literally talking to Satan, yet, he was looking at Peter, and the words came from Peter's mouth. This is a very significant part of Scripture as far as I'm concerned, and I don't think most people understand the depth of the meaning here.
There is more going on here than what we can understand and demonstrate rationally, no matter how smart we may think we are.