Talk about getting a grip. Methinks the Puritans and their modern day descendants would have "Santa" unmasked as an anagram and consigned to flames for putting the "merry" in Christmas!
People get wrapped up over the little things that they overlook the larger picture. The Myth of Santa does not push out Jesus from the Holiday, but shows what the effect of Jesus had on others that Nickolaus' influence has become world-wide and spanning the centuries. Maybe not in a historial sense, but it is fun for the whole family.
There are those who do take the Santa thing too far, but that is the minority.