Now, marketing Santa has been portrayed as white. If your points are targeted towards marketing santa then why the f do you care if a little kid that's not white asks why a FICTIONAL MARKETING character can't be his color as well?
It's fiction. No skin off your back. It's no different than making a dwarf in a story into a troll in order to make a little kid happy.
Also, last I heard, nobody has "seen" santa.
Its like saying Bugs Bunny is a cat. Everyone recognizes bugs bunny as a rabbit and we would correct anyone that called him a cat despite the fact he doesn't actually exist.