yes yes of course Christmas makes us feel good and makes us feel happy, but if we found out Lucifer was born on December 25th and Jesus was born on Sept,11th and we still celebrate Christmas as the day our messiah was born would that be wrong?
That isn't the point,any holiday is not simply about,"a day" it's about who or what is being celebrated and how one celebrates,say for example if on either day a person praises Jesus but their actions please the devil,said person is actually praising satan but using Jesus's name to hide behind,now as to "intentional rejection" of Christ's birth that is quite different because it leads to rejecting Jesus altogether,his birth is important,the day is of no consequence when we seek to celebrate his birth,after all since when have our generations ever been "perfect"?
God understands that we will err,so any celebration of Jesus by anyone that is "right" to do in God's eyes,is acceptable.
For to celebrate Christ is to celebrate God whom sent Christ Jesus for our sakes to walk and die as a man,but resurrect and ascend and give us the holy spirit and the gift of salvation.
It is just as it is written of fruits,a celebration just as a tree shall either bring forth "good fruit" or "wicked fruit" it cannot produce both,as in if a celebration is pleasing to God/Jesus then it is acceptable and possibly may add more souls to him,but if it be filled with things opposite to God/Jesus(drunkeness,cursing,idolatry,and so on) then such a celebration is unacceptable to God and pleases only satan and one's self.