Mild Last Jedi spoilers:
The movie is about...
1. Perspective: Everyone is the hero of their own story. Everyone has their own perspective on events. Everyone feels justified in their own behavior.
2. Leadership: There are many ways to communicate and lead. Some are successful, some are total failures. Some engender trust, some get results, some can lead to disaster.
3. Letting go of legacy: Both sides argue for sweeping away the past and creating a new kind of future. Let it die. Let it burn. Time for a new approach. Ironic given that the Force Awakens borrowed so much from the legacy of the franchise.