I don’t think we’ll ever know the full story, or more precisely, who they were working for and why.
The official story will probably be that they were running a high for the rich and powerful end prostitution ring in which underaged girls were involved. It’s a big scandal, but nothing anyone would be super shocked about. There’s several celebrities who are known to have had sex with underaged kids who are doing just fine today.
What was most likely actually going on on that island is a so called Honeypot trap. They probably had the same employer as Maxwell’s father.