St. John Chrysostom
“Only the person who becomes irate without reason, sins. Whoever becomes irate for a just reason is not guilty. Because, if ire were lacking, the science of God would not progress, judgments would not be sound, and crimes would not be repressed.
Further, the person who does not become irate when he has cause to be, sins. For an unreasonable patience is the hotbed of many vices: it fosters negligence, and stimulates not only the wicked, but above all the good, to do wrong.” (St. John Chrysostom, Homily XI super Matheum, 1c, nt.7)
St. Thomas Aquinas
“Ire may be understood in two ways.
In one way, as a simple movement of the will that inflicts punishment not through passion, but by virtue of a judgment of the reason: and in this case, without a doubt, lack of ire is a sin. This is how Chrysostom understands ire when he says: ‘Ire, when it has a cause, is not ire but judgment. For properly speaking, ire is a movement of passion. And when a man is irate with just cause, his ire does not derive from passion. Rather, it is an act of judgment, not of ire.”
In another way, ire can be understood as a movement of the sensitive appetite agitated by passion with bodily excitation. This movement is a necessary sequel in man to the previous movement of his will, since the lower appetite naturally follows the movement of the higher appetite unless some obstacle prevents it. Hence the movement of ire in the sensitive appetite cannot be lacking altogether, unless the movement of the will is altogether lacking or weak. Consequently, the lack of the passion of ire is also a vice, as it is the lack of movement in the will to punish according to the judgment of reason.” (St. Thomas Aquinas, Summa Theologiae, II, II, q. 158, art. 8)