Livre d'Or

I think because they had a basically colonialist mindset. They thought it was completely horrible and barbaric to have ship-minds, they were repulsed by the idea of giving birth to machinery or having a human mind instantiated in a non-organic body. Plus, not coincidentally, the ship-minds posed a major military threat to the Federation. So they convinced themselves they were doing those poor Dai Viet people a favour by kidnapping the ship-minds from their home culture and making them into "normal" humans. And then they discovered that the ship-minds were driven to suicide by being confined to bodies, so they reprogrammed them so they wouldn't miss their previous existence as much.

It seemed to me like a very direct parallel with the American adoption industry, the religious Christians who genuinely believe they're doing those poor kids from uncivilized lands a favour by paying agents to literally kidnap them from their parents and market them as orphans, and bringing them over to the US and bringing them up as English-speaking Christians. Denying them any access to their own culture and completely ignoring the fact that their appearance makes them stand out a mile from most of their white, European-descended neighbours. You can imagine if they had access to literal brain-reprogramming technology they'd be all over it, as it is they only have education and behavioural therapy which isn't torture honest.