Well, as we all know the Blacks tend to be forced to survive on their own, no place to call home and have only themselves to look after and watch their back. That is a hard road, requires a strong will and fortitude to stand alone against the harshness of Gor.
The Scarlet on the other hand does not have the freedom to just walk away and travel where they want. A warrior must rely on his brothers to guard his side in battle, even if it is the same man we fought over a slave hours before. A warrior must stand firm against whatever comes roaring over the hill to protect their homestone, even if they know it means certain death. A warrior is that thin red line that gives himself so that other citizens may live in some semblance of peace.
IMO it is the idea that the Scarlet are willing to sacrifice themselves for homestone and honor that gives them the edge over Assassins. Even though some call us Scarlets fools for such an ideal.
“I'm not in this world to live up to your expectations and you're not in this world to live up to mine.”
“For it is easy to criticize and break down the spirit of others, but to know yourself takes a lifetime.”