You cannot control what others think, say, feel, or do. You can only control yourself and your responses to situations; others are responsible for their own actions. Accepting this can remove a great deal of stress from your life.
Determine which battles are worth fighting and which are a waste of time and energy. Choose to participate only in those you believe are worthwhile and that you have a chance of effecting positive outcomes. If a discussion starts escalating out of control, walk away and perhaps try at another time.