I don’t see how this is so heavily downvoted…? It makes complete sense that humans (by far most of which live in the northern hemisphere) would celebrate that the darkest days have passed and that we’re heading from a dark and harsh winter towards a promise of spring. Coming from the north, I can definitely testify to the fact that you feel in your whole body that the days start getting longer.

The fact that the exact date is slightly off basically amounts to a rounding error, and making a point out of it is just pedantic.