It's not difficult to think of realistic (if not necessarily sensible) motivations if we try. Maybe they're religious fanatics and there's no we can satisfy th

It's not difficult to think of realistic (if not necessarily sensible) motivations if we try. Maybe they're religious fanatics and there's no we can satisfy their tenants so.. Or maybe the local alien boss doesn't want to deal with their EPA equivalent and decides to deal with the problem before anyone notices. Or the Grand Poobah just acts whimsically and everyone must do as it says.