Some profound thinkers posit that we create our own reality and it is all illusory. If true what is the point of arguing or fighting?

How can be a right or wrong, good or bad if it is all illusion? How does that make any sense? We fight over what we imagine a world we create to be and it isn't? How useless is that? It's like fighting over a novel that someone creates out of imagination. Who does that?