The Detemen League that rebelled against their rightful overlords never intended to free their home planet from the greedy nobles that exploited it dry. They wanted to make a statement that would shock the entire Kingdom, and to accomplish this, they intended to tear down the depraved heir that ruled over Detemen IV.
They never intended to stick around after initiating the riots. When the Vesian reinforcements came in force and started to scour the planet, most of their hideouts would doubtlessly be found. Instead, they already prepared to escape in space and rely on the Vesian Revolutionary Front to shelter them far away from their homes.
Since they only prepared a limited amount of ships, they couldn't bring everything they owned with them. The ships would only be enough to carry their core members along with some basic supplies and trade goods that they intended to barter for survival in the stars.