Perhaps he thought the dangers that were coming after you would need someone who was simply ... that extreme? Your impression of your father seems to be that he was an intelligent man, one who loved you very much. Perhaps he thought to put the largest dog before the gate, knowing it would bite.

[Hannibal shrugged elegantly. All of this was conjecture, after all. He had not met Jyn's father. He could not guess at his motivations.]

Perhaps he just wanted to ensure you would survive to adulthood.