why, after 1765, did the American colonists increasingly find British imperial rule unacceptable? What had changed -- and why?

Answer 1

The British increased the colonists' taxes with the Stamp Act and later the larger tax on tea.

Answer 2

well there was a stamp act passed that put taxes on on a bunch of stuffs like newspaper. People were mad about this and they thought Britian was treating them unfairly and taxing them for no reason.