Barbarism is barbarism, thoughout the colonies. Murderers are the sick detritus of their societies, created by the self-satisfied first-stoners, as you know. How will murdering a member of another one help 'the family' then?
Let me be the first to say I am opposed to the death penalty in all situations (terrorists should be shot to death during "capture".)
However, Winterborn is one of the most rational people here, and I must point out you are painting him with a rather broad brush. There really is an enduring frustration about losing the "colonies" isn't there?