The first thing people need to understand is what it means to be relative. It means that depending on perspective contradictory statements can be true at the same time. For example if we face in opposite directions everything on my left is on your right. If I say something is to the left and you say it is to the right we are both correct at the same time.

However, if I say that an object is to the north of us and you say it is to the south, one of us is wrong. The north/south designation is not relative.

It has nothing to do with disagreement, it has everything to do with saying that both opinions are equally valid and equally right.