What to do with true psychopaths is an interesting question. Sea-steading is a concept that billionaires such as Peter Thiel, are considering as a way to escape government interference and ensure personal security. Such man-made self-sustaining islands could be constructed and true psychopaths might be banished to these islands to live out their days where they won't be a danger to the general public.

Separation from people seems the only way to ensure true psychopaths might be prevented from damaging their surrounding humans. I would only suggest this for psychopaths at the high end of the spectrum. Serial rapists and pedophiles could also be quarantined on these islands due to their inability to change and their danger to people who surround them.