While there are certain cases where names are truly surnames and not proper names, that you cannot forget that many surnames are in truth, proper names.
Take my own name, for instance. Ostensibly, I was named after the surname of two of my great-grandparents, ------son, and so my name is ------. However, when you think about it, that really just means that I am named after my distant ancestor, the father of the first to use the name ------son.
Of course, giving your daughter a first name that ends with -son, now that is really distasteful, hehehe... And yet, for some reason, people do it.