If we are agents in a lab, then certain drives are hard-coded into us so we move, act, and make choices the creators can learn from. Reproduction and raising children is one of those drives. Even people who say they never want kids because they just want to "have fun" often regret it later — which shows the hard-coding was there all along, but they got swayed by the cultural currents.
In that case, culture isn't just a byproduct of human actions. It can be a deliberate variable introduced by the creators. They can push an idea into the culture, then watch what happens when it collides with our biological drives. For example, if the culture tells people to avoid kids and chase shallow pleasure, the simulators can observe how many people regret it, how societies change, and what long-term effects appear. We become a massive A/B test for social engineering.
But it does not serve us to look at the simulation as a lab — because it's a lab for the simulators, not for us. A far more useful view is to look at it as a game.