The area of economics that uses value judgments to make recommendations for future actions is normative economics. To do so, normative economics analyze the possible way an economy should work under certain ideal circumstances.
That being said, normative economics is just opinions of economists that say what they think might happen to an economy judging by circumstances. It can either be true or false, it depends on who believes it.
Normative economics makes judgements related to economic events and decisions, in order to conclude whether these are fair or adequate in a specific situation, or in order to assess the validity of the goals and results of the public economic policy.
This dimension in the study of economics is defined in opposition to positive economics, the branch within economics that describes and explains economic phenomena, without making any judgement.
This quotation presents a justification for reformation or rebellion of a tyrannical government. "whenever any form of government becomes destructive of these ends, it is the right of the people to alter or abolish it"