I’m not sure what you think the admins did to make other people settle there.
They opened the gates and let people come in without knowing if they were able to handle the influx of people. By presenting themselves as a place that could welcome everyone, they end up robbing the opportunity for other instances to share the load and to absorb part of the user base. This is what I mean about “land grab”.
A more sensible approach would be to have a feedback loop where they open up a limited number of spots, fill them, see how their instance and the overall fediverse behaves and adjust based on that new information.