British colonization of North America wasn't a British crown enterprise. Settlers came to North America for different reasons in a more localized and smaller initiative. They remained free to organize themselves politically as they preferred as long as they obeyed English law.
Colonization made by other European countries, namely Portugal and Spain, for example, were made in other to enforce the crowns of each. Colonies had no political freedom and were ruled by the crown's appointees. Spanish and Portuguese colonization of the Americas were made to increase Christendom and the crown's territories. It served to reassert the power of the Christian rulers of Portugal and Spain who were ideologically dependent on the support of the Church.