The secret to creating enhanciles that don't go homicidally bonkers is to remove their memories from when they were fully human.
They go mad because they know what they've lost. Similar situation to cyberman emotional inhibitors
or Stalkers. If the alien infrohazard hadn't been stopped, it would've forced its infectees into broadcasting copies of it back into space towards even more planets.
Like some kind of quasi-sentient mind rapist chain letter.