I suppose he means just because you admit the truth about yourself, free of diplomatic sugar-coating and rationalizing stultification, doesn't mean you are exonerated by that truth.
How often people take it as badge of honor to "tell it like it is", without really facing the goodness of badness of how it is. As St. Josemaria Escriva said, "You say you cannot change. 'That's just my character,' you say. No, it's your lack of character!" By subjugating knowledge of the truth to conformity to it, we have subjugated goodness to bluntness, virtue to "being real". A show like "The Real World", for example -- even aside from its preposterously unreal "hiptopia" of affluence -- is not about people "being real"; it's about people choosing to let a series of edited "encounters" justify their behavior at any moment in that series, as if the sheer reality of an action explains or justifies that action. Yet, the stark reality of immorality as "human nature" is itself a lie as to what human nature is. Affirming who we really are is probably the easiest way to erase who we should or could be. "Being real" while still being corrupt is as good as framing a perfect photograph of a counterfeit. Declaring the truth of such and such a case of wickedness is leagues away from the virtue of declaring the truth of goodness in any case. Let us dare utter the truth only when it is an expression of a deeper goodness -- in the words of St. Paul, to "speak the truth in love" (Eph 4:15). After all, the same Apostle urges us in the same epistle:
[4:22] Put off your old nature which belongs to your former manner of life and is corrupt through deceitful lusts, [4:23] and be renewed in the spirit of your minds, [4:24] and put on the new nature, created after the likeness of God in true righteousness and holiness. ... [4:29] Let no evil talk come out of your mouths, but only such as is good for edifying, as fits the occasion, that it may impart grace to those who hear. ... [5:11] Take no part in the unfruitful works of darkness, but instead expose them. [5:12] For it is a shame even to speak of the things that they do in secret; [5:13] but when anything is exposed by the light it becomes visible, for anything that becomes visible is light.
We are not to speak of wickedness neutrally, objectively, journalistically as "hard facts of life". Rather, we must speak -- and in fact let our lives bespeak -- the truth of goodness found in Christ; and the truth of goodness will by its very nature shed light on "the reality of evil" as detergent impinges on dirt. Why scare-quote "evil"? Because evil is a metaphysical unreality, an illusion of freedom pretending to stand independently in defiance of the only reality we possess: God's goodness imputed to us as beings and His goodness infused in us as His children.
We mustn't face the truth about ourselves as an excuse for ourselves. Rather, we must seek the truth about ourselves, among our neighbors and before God, as a means to attain the fecund, relational and ultimately sacrificial goodness that truth articulates in so many ways (ie., language, philosophy, art, liturgy, literature, music, poetry, art, dance, exercise, etc.).
At bottom, I believe Fakespeare is exhorting us not simply to speak the truth, but to speak goodness truthfully.
But that's just my take on it.