Alma 54

As Moroni and Ammoron write epistles one to another, I note a portion of each of their purposes.  First Moroni and the Nephites being -

"...we will retain our cities and our lands; yea, and we will maintain our religion and the cause of our God."  (Book of Mormon | Alma 54:10)

"...and we have only sought to defend ourselves."  (Book of Mormon | Alma 54:13)

Ammorons purpose knowing it was false and had no basis -

"...your fathers did wrong their brethren, insomuch that they did rob them of their right to the government when it rightly belonged unto them.
18 And now behold, if ye will lay down your arms, and subject yourselves to be governed by those to whom the government doth rightly belong..."  (Book of Mormon | Alma 54:17 - 18)

Obviously, Moroni's purpose was just.