The Mech Trade Association and by extension the Red Association craved power.
It was in the nature of a dominant organization to do whatever it took to preserve their dominance and reduce the ability of others to overturn its reign.
The mechers had never made it a secret that they were cast from the same mold. Their deliberate attempts to castrate the many states of human civilization successfully prevented other human groups from growing too strong during the Age of Mechs.
Ves never really had a problem with that for the most part. The hegemonic model set by the Big Two after the disastrous end of the Age of Conquest led to centuries of growth and stability.
It was difficult to think of another alternative that could have led to a more favorable outcome for human civilization.