Well, as far as I know, those who celebrate(d) the solstice were/are a "religious lot" too, Paul. Of a non-Christian stripe.

Litha (or Midsummer, June 24) became the Feast of St John the Baptist after Europe was Christianized - an important holiday especially in French-speaking countries.

Just as Aug 2nd, ie Lammas (or "Loaf-Mass", the first harvest) became the day when the Eucharist loaves for the year were baked (ie from the first wheat harvested), and blessed by the Christian priests.