Maybe they're focused on not dying and other priorities over makeup? The Drengin are not going to go and say "oh, nice eye shadow, we will not enslave your race now."
This conversation is mind numblingly stupid.
I don't think the Altarians have much to worry about being enslaved.
For one, they threatened the Drengin and Yor with doomsday weapons, left on Altaria by the Precursors, should they dare to invade. Second, Altaria is uninhabitable for other races for some reason, so an occupation is impossible. Third, the Altarian home-system is being blockaded by the Yor. So, if anything, being wiped out from orbit by the Yor is the far bigger threat.