May I suggest a thorough reading of Romans 14.
Paul does not say or intimate that perspective changes the truth--in fact, he explicitly notes that judgment is the Lord's. He was counseling how to get along with folks who have different habits--vegetarian or not, for example. I don't understand what that has to do with the immutability of truth and whether the truths is actually different, depending on your perspective.
Elsewhere, Paul was pretty hard nosed on the issue of the truth we were discussing previously--the messiahship of Jesus.