Sounds like an advanced version of ancient tribal performative warboth groups gather, yell, taunt, throw some spears (that likely hit nobody) maybe actually skirmish somebut then disperse. (This can still be seen with some indigenous peoples today) While i doubt large ancient armies did exactly THAT, they very well may have fought in a similar style. Have at each other, break it up, drag away the wounded, yell taunts, give a fiery speechand back into the breach until one side submits.