Truth can be perceived as a threat.

Thereafter, spirit is perceived as a threat, because light abolishes darkness merely by showing you it is not there. Truth will always overcome error in this way. This cannot be an active process of correction because, as I have already emphasized, knowledge does not do anything. It can be perceived as an attacker, but it cannot attack. What you perceive as its attack is your own vague recognition that knowledge can always be remembered, never having been destroyed. T-3.IV.6:6-10

A Course in Miracles . Foundation for Inner Peace. Kindle Edition. 

The sayings are: “The truth hurts,” and “What hurts, the message or the messenger?” Truth is often perceived as a threat because what one believes and has identified with and invested in turns out not to be true. It is written in A Course In Miracles “Would you rather be right or be happy?” Many people choose not only to be right but to physically die for their belief system rather than change their minds.

In Alcoholics Anonymous it is suggested, in step three, that we make a decision to give up our willfulness and turn it over to the will of God. In making this decision, we choose happiness rather than stubborn insistence that our ego is right.

In Unitarian Universalism, we covenant together to affirm and promote the free and responsible search for truth and meaning. This often involves giving up the “faith of our fathers” and going our own way in search of the truth. This decision often hurts when we get blowback from those we have been in relationship with.

Today, it is suggested that we consider that Truth is often considered a threat to one’s own self concept and to what one believes about the world. It is further suggested that this consequence of truth is not an attack but simply an invitation to give up one’s illusions.