What if hostility is a feature? They have a culture that works for them. Many organizations do not survive massive influx of new members - numbers inflate quickly, community adapts rules because you cannot manage a big community the way you'd manage small community, old members leave, new members get bored and also leave, the community tries to manage a small community the way you'd manage a large community, whole thing collapses. Meanwhile if you're hostile to new members you avoid unsustainably high expansion and complete collapse of the organization's management structure because there is no expansion. Expansion is not a measure of success if it sacrifices maintaining current culture. Asian societies famously function like that.