Public rallies and civil riots in "Freeze Age 2" are a direct result of the relationship between players and factions in the game and their interrelationships. Rally is organized by factions with good relations to support you, and riots are organized by factions with poor relations. Factions organized to attack you.
What is the difference between a rally and a riot in Frostpunk 2
Rallies and riots are a direct result of your relationships with factions and their relationships with each other.
Rallies are caused by increased enthusiasm and good relations between you and a faction.
Riots are caused by increased enthusiasm and negative relationships (with you or other factions).
In the main story, only two factions are able to hold rallies and initiate riots. These two factions sit in the middle of your relationship bar and are the only ones whose passions can be viewed. For example, if you choose the Faith route, the two factions would be the Faith Keepers and Evolvers; similarly, the Order route would include the Stalwarts and Pilgrims.