Why did the British change their attitude to royal power so dramatically during the 17th century revolution?

Because the royal power sought to maintain the old order and further strengthen the feudal power. Thus, the king became not only the enemy of parliament, but also the enemy of the entire English people. This led to the fact that in 1649 the captive king was executed. By 1653, it was possible to extinguish all the centers of unrest in the country. In the same year, Cromwell’s protectorate was established.