Why did some Protestant churches reduce or abolish most church-year observances after the Reformation?

During the Reformation, Protestant reformers approached the church year with varying degrees of radicalism, driven by a commitment to the authority of Scripture and a desire to free the gospel from what they perceived as human-made legalisms in liturgical practice.1

While some groups, such as Lutherans and Anglicans, maintained a conservative approach by keeping traditional seasons, others—specifically Reformed churches, Puritans, and Anabaptists—sought to purge the calendar of observances that lacked a clear basis in the New Testament. These groups often abolished the church year entirely, except for Sundays, to emphasize that all days belong to Christ and to reject what they viewed as rigid, man-made systems of fixed special observances that could distract from the freedom of the Spirit. This movement was part of a broader effort to "purify" worship of remnants of Roman Catholic practices, which were frequently characterized by reformers as "popish idolatry".12