There is a footnote on the word “rash” that has me considering its meaning and also contemplating past decision that were made rashly, or in haste.
Rashness when resulting in anger seems to be a faulty formula, and maybe this is where anger can be acceptable when separated from rashness (that is, acting quickly or hastily as a result of something provocative.)
There are a couple of other brief thoughts. Moroni was angry with the King-men that thought because of their nobility to place themselves upon the corpus of the Nephite people.
And it came to pass that when Moroni saw this, and also saw that the Lamanites were coming into the borders of the land, he was exceedingly wroth because of the stubbornness of those people whom he had labored with so much diligence to preserve; yea, he was exceedingly wroth; his soul was filled with anger against them.Verse 14, emphasis added
Then as I read about the needless suffering and destruction that took place as a result of the King-men’s opposition to the government which allowed the Lamanites to overpower and kill many good people, and I could help but feel a degree of anger, pain, and sorrow for the pride that cause this to happen.