I'm starting to see that you have no idea of the concept of Sacrifice for the greater good. They chose to fight due to the fact that they knew they had to keep the guards at bay so you could run to clear your names. Lolorito, the brass blades, and the Crystals Braves were ready to lynch mob you to burn you and everyone at the stake.

You were weaponless and defenseless due to your visit with the Sultana and even then when Thancred and Y'shtola were about to stay Minfillia ran off while you stayed behind like you wanted to fight. When Minfillia went to go back you argued with her about it and with the dialogue the way it was atleast in english you wanted to stay but you knew you couldn't because of the burden you have as BEING the Warrior of Light.

I have a question how many fantasy books do you read? (and this isn't a provoking question it's serious) Because in damn near a lot of the ones I have read there is always someone or a group of people who will sacrifice everything to keep the hero from being harmed. Weither it's keeping them from being killed by taking the blow for them or by staying behind for capture so the one who is innocent can escape.