We can blame the Puritans, or rather the misinterpretation of Puritan practice of not celebrating Christmas, limiting or banning alcohol consumption, prohibiting theatre, games of chance, card playing and more.
The Puritans were those who came on the Mayflower to North America, escaping religious persecution in Europe. They originated in England in the mid 1500’s (about the same time as Martin Luther began his protest against the Catholic Church). Some fled to the Netherlands in 1608 and then on to North America in 1620. What drew them together was a belief that the excesses of the Catholic Church must end. They did not believe that the Church of England had gone far enough in reform.
They saw the riches of the church, the lavish lifestyles of some of its bishops, and the sexual promiscuity developing in society, and they firmly believed that this was not how Christians were to live. They wanted to “purify” the church and simplify the way of Christian living. Because of this, the Puritans became known as killjoys, considered overzealous in moral living and joyless in their approach.
The Puritans eventually became the Congregationalists and, in Canada, the Congregationalists eventually joined the union that led to the United Church. So we have these Puritan roots. But I think something was lost in the messaging through the centuries. The original Puritans did believe in joy – joy in the Lord, joy in faithful living, joy in faithful relationships, joy and delight in their children.