The people living there are mostly descendants of the Bounty mutineers and their captives. There has been a long sad history of sexual abuse, with one third of the island's male population being convicted and imprisoned in the early 2000s. They were let out of prison to do jobs, such as unloading cargo ships, during the day because the island could not function otherwise.
There really are not many jobs to be had so migrants are not allowed to take local jobs, I guess they have to create a new job for themselves. According to Wikipedia they used to get 700 enquires a year for migration but nobody ever actually applied.
I am surprised nobody has tried using it as a stepping stone to get into New Zealand, because the Islanders can live and work indefinitely in New Zealand if they are of good character and good health.
Edit: I did not want to sound disrespectful so I edited my comment slightly.