Did it really matter that Christ was born in a shed and laid in a feeding trough? It’s not like being born in Bethlehem; that was to fulfil God’s promise in Micah 5:2. And it’s not like being a son of a descendant of King David; that was also to fulfil God’s promise (2Sam7). As far as a I know, there’s no promise that the Messiah needed to be born in a shed.
But there is Isaiah 53:2-3
He grew up before him like a tender shoot, and like a root out of dry ground. He had no beauty or majesty to attract us to him, nothing in his appearance that we should desire him. He was despised and rejected by mankind, a man of suffering, and familiar with pain. Like one from whom people hide their faces he was despised, and we held him in low esteem.
When God said that his Messiah would have no beauty or majesty… when He said the Christ would be held in low esteem… maybe the manger is one of the things He meant?
And that means something wonderful for us. Well, particularly for those of us who are held in low esteem, who feel we have no beauty or majesty. God’s Son lowered himself to your level, even on the day of his birth.
The son of God associated himself with the lowly and the forgotten and the despised and the laughed-at — all from the word go.
Why the manger? So that no-one would ever be beneath him who is above all.