Perhaps he was acting suspicious as well, at least in the woman's opinion.
This is why I mind my own business. Unless the guy was obviously shady, or the kids looked under duress, I would have went my merry way. With social media today you will be immediately tar and feathered as a racist worldwide, with little recourse to prove otherwise. And there is always a SJW parent to happily see to it, as we see here with these kids’ father.
60 years ago a black man would have been questioned for being with a white woman.