It has to do with determination and the rightfulness and truthfulness of ideas.
From the heraldtribune.com
Have I assumed the automatic right to judge the honesty and rightfulness of benefit claimants?
From the guardian.co.uk
Judges tell juries that they do not have the power to judge the rightfulness or wrongfulness of the law that the defendant is being charged with.
From the infowars.com
Border troops interviewed in the film described what they saw as the rightfulness of their cause and the threat of Western agents, spies and provocateurs.
From the en.wikipedia.org
More examples
Right: anything in accord with principles of justice; "he feels he is in the right"; "the rightfulness of his claim"