Namely, by creating 2 points of pressure that doesn't originate from any Civ in particular, it causes a situation in which the highest tourism/culture generators of a different ideology suffers the most unhappiness.
This is due to the fact that you can be pressured by an Ideology that is the same as yours, but only if the source of that pressure has higher tourism.
Let me explain:
Say Hiawatha, Haile Selassie and Sejong all go Freedom, with Hiawatha being far and away the biggest contender for a cv with some 300+ tourism, while the other two are still on ~40.
Say a World Congress passes the "World Ideology: Order" measure.
Hiawatha will now find himself with 2 hammers of pressure originating from no-one in particular.
Ethipia and Korea also feel this, but they are getting 2 Torches of pressure from their Iroquois brothers, so paradoxically being lesser cultural powers they are "Content" while Hiawatha is at Dissidents.
This is due to the fact that you can be pressured by an Ideology that is the same as yours, but only if the source of that pressure has higher tourism.
Let me explain:
Say Hiawatha, Haile Selassie and Sejong all go Freedom, with Hiawatha being far and away the biggest contender for a cv with some 300+ tourism, while the other two are still on ~40.
Say a World Congress passes the "World Ideology: Order" measure.
Hiawatha will now find himself with 2 hammers of pressure originating from no-one in particular.
Ethipia and Korea also feel this, but they are getting 2 Torches of pressure from their Iroquois brothers, so paradoxically being lesser cultural powers they are "Content" while Hiawatha is at Dissidents.