Defending By Accusing

It has become common practice in contemporary rabbinic literature to resolve ancient Talmudic and medieval disputes by positing that both opinions are essentially true, and each position merely highlights a different aspect of the same core principle.  In asserting that both opinions are true, the implication is that the proponents of both opinions erred in stating that the opposing position is categorically wrong.  Is it better to defend both positions as truthful, implying that the proponents of those positions are both in error, or to acknowledge that one position is right, and the other is wrong?