Of all the CorpoNations in the War, Rimtech is the balanced of the three, with its Combot parts focusing equally on offense, range, defense and maneuverability.
The Angelus brothers all worked for Rimtech before they split up after the incident on the Hedoth system, and now only Diego Angelus remains part of Rimtech. Their father, legendary combot ace Icarus Angelus, also worked for Rimtech.
"If the righteous and honorable can also obliterate you, who are you to argue with their vision of the galaxy?"
Rimtech also seems to be the "better" good between the three factions.