Well honestly the best idea would be for them to be kept separate, and made to form new bonds with people who aren't raiders, to help dissociate them from their past lives.
That does sound like a pretty good idea, provided that we can find people they'd be willing to form genuine bonds with, and who are willing to form genuine bonds with serial murderers in turn. These people certainly exist, particularly if we include the non-magical population into the pool of potential bonds, but it's probably going to take a while to find them and cause the formation of bonds with them. This solution may have a longer time horizon than the Fukushima group is willing to accept, given their reluctance to be indefinite jailors.
It is only our lack of resources and time that is preventing us from getting the rehabilitation programs started. The current imprisonment was always intended to be a temporary measure done in order to avoid the Freezer like we went with for Rionnnna. Personally, I think the Freezer would have been a more humane temporary option, but the thread concensus was against me on that one. Presumably because it would be a lot easier to just forget about someone in the Freezer and let the temporary measure become defacto permanent without us meaning it to than it would when said girls are still conscious and able to complain about their conditions.
That helps assuage my concerns quite a bit, although it does raise the question of why underground containment was brought up in the first place.
Also, to add my thoughts to the ongoing conversation concerning magical anarchy, I think one thing that is being omitted from the debate is the external forces that may act upon the magical community and the impact that they may have on the viability of anarchy. I think we've been acting under the assumption that magic will eventually be exposed to the non-magical community as a necessary consequence of our objective to end magical scarcity, so I won't dwell over that logic. Under that assumption, I think we'd need to consider what non-magical states may choose to do in response to this revelation. I think the notion that they would seek to exploit magic for both internal and external security, among other things, is uncontroversial. Therefore, the magical community needs a way to counter misuse of magic by states aiming to attack other states, conduct espionage on other states and/or their own citizens, or to ensure the internal security of the state by suppressing dissent. This need is accentuated by the real possibility that states with insufficient respect for liberty--which, for our purposes, is most of them--may seek to pressure individual meguca or small groups of the same to aid them, whether through social pressures, coercive force aimed at their loved ones/community, or direct coercive force. We also can't discount the fact that meguca who are attached to their countries or who want the compensation that states can give may join states willingly and abuse their powers under the state's authority. I think it's clear that localized mutual aid, or even ad hoc reactions from the magical community as an uncoordinated whole, would not necessarily be able to respond to this threat adequately.
Other external forces, such as terrorist groups, criminal organizations, and the Incubators, may also act upon the magical community in ways that threaten the viability of anarchy, but if I keep going on about them, this post will turn into a full-blown essay, so I'll leave it at this for now.