Justifying disparate human cultures and empirial forces in a galaxy spanning sci fi setting

So I'm not exactly sure the best way to justify multiple human "factions" in a galaxy spanning sci fi setting. My thought was to have the seeds of separate civilizations spawn from a conflict in the past when humanity was still locked to their own star system. The sides in that conflict then undergo a diaspora post conflict (for a few reasons, none of which are important here), settling many of the distant known habitable planets in different parts of the galaxy where they then continue to develop on diverging paths. Does that make sense and seem like a feasible explanation?