I believe that Mr. McGraw put it as plainly as possible. The people of Ebott's Wake must keep their heritage alive, and part of that heritage includes resistance to tyranny, no matter how that tyranny may present itself. 

I'm afraid largely the events have been organized by King and Queen Dreemurr, and while I am privy to their agenda I wouldn't want to steal their thunder.

Well, first we must start with general background. The legal status of monsters has remained unclear ever since the Barrier under Mt. Ebott was destroyed.