His opening line says a lot about what Christmas is about. Sproul says:
What we celebrate at Christmas is not so much the birth of a baby, as important as that is, but what’s so significant about the birth of that particular baby is that in this birth we have the incarnation of God Himself.
In celebrating Christmas, we are not to celebrate family, peace and good will to all, or some idealism that unites as many people as possible. It isn't as if those things should be dismissed. It is that Christmas has a specific meaning and that meaning revolves around the birth a one particular baby who was God with us. And that was a feat that the birth of no other child could accomplish. In terms of defining Christmas based on who Jesus is, Sproul does a wonderful job and what he said is well worth listening to or reading.
But I would add one more point to what Sproul said in his talk. Christmas is about the birth of one particular baby within a specific context. That context was God's love reaching out to a fallen world. Now describing the world as 'fallen' does not do emotional justice to the state of the world both then and now. And because it does not do justice to the state of the world, it also does not do justice to our own individual states. God came to us in person starting with the birth of Jesus because of His love for us and how sinful we are. The problem of our fallen sinful state could in no way be remedied by some moral nerd who could teach us how to live better lives--though we should always appreciate those moral nerds who do. Rather, our sinful state required that God Himself must repair the damage that sin has done and He came to us up close and in person to do just that.
The inclusivity of how we celebrate Christmas today diverts our attention from the birth of the one particular baby named Jesus. Also, the conjunction of that inclusivity along with our consumeristic approach to celebrating Christmas distracts or even blinds us from the sinful state that Jesus came to rescue us. Because of the inclusivity of and our consumeristic approach to celebrating Christmas, Christmas time has become merely another escapism that is joined by so many other forms of escape. And what we are trying to escape from is seeing Christ for who he is and ourselves for who we are. For seeing Christ for who he is can be frightening and seeing ourselves for the sinners we are can be too painful. In addition, seeing ourselves for the sinners we are robs us of the relief we get from focusing on the sins of others.
So please either read or listen to the talk Sproul gives about the meaning Christmas. I deliberately did not comment too much on what he said so that people reading this would listen to or read Sproul's own words.