Dumbledore references the French Revolution, probably for its perceived bloodiness, as a warning. If Harry does intend to lead a revolution, he might do well to quote from the U.S. Declaration of Independence "when a long train of abuses and usurpations, pursuing invariably the same object evinces a design to reduce them under absolute despotism, it is their right, it is their duty, to throw off such government". That seems to be the case for the Half-bloods and the muggle-born in the wizarding world in England.