They were merely noting the natural propensity for intelligence to discern between what to love and what to hate. All surviving creatures have such instincts born within, else they could not survive as a species (even insects).
Psychologists (just barely on rare occasion fitting into the category of “scientists”) most certainly cannot be trusted to experiment and attempt to analyze complex systems or creatures more intelligent than their own cognitive comprehension skills. Infants fit into that category, as do almost all animals. The cognitive comprehension skills of the average psychologists are embarrassingly low. More to the exact point, none of those psychologists in that video actually understand what “morality” is. That is an issue for philosophers to decide. And no science can be conducted without proper definition. Ask any of them to exactly define “morality” in an unambiguous way. They would probably tell you that such isn’t necessary, which is largely why they are (still) not really qualified to be referred to as “scientists”.
Anyone can trump up what superficially appears to be a scientific experiment with all of the buzz words in place: “this was a double blind study”, “81% of the non-control group responded positively”,… The sad fact is that most people doing such things are very, very sloppy and often have ulterior motives.
Ask what the scientific definition of “morality” is. Without such a precise definition, no measure of it can be scientifically made.
And all of that is not to discount Arminius’ point that the very concept of morality, and thus good and evil, does not apply to animal behavior, and that includes human infants. Homosapians aren’t all that much different than other animals. What doesn’t apply to other animals only might barely apply to homosapians.
Your psychologist references are off mark for the same reason that you are - a complete lack of understanding of what morality and evil actually is and is actually all about.