I think Miles feeling like his father would be disappointed in him is far more interesting if he came to that conclusion by himself instead of being "taught" to believe so by an external factor or being somehow trained to be something Gregory would have "hated" (and let's be real, Gregory would not flip a switch and hate anybody for anything, let alone his son).
Miles feeling like this by himself means there was a moment of self-reflection, even if that reflection did not reach the actually correct conclusion. It offers opportunities to explore how his brain works, themes of survivors guilt and grief that linger long after dl-6. That's interesting! That's intriguing!
What do you get from deciding there was some grand plan to form him into "a person Gregory would hate" (despite the obvious problems with that logic in the first place)? Cartoon villainy I guess? That's not very fun to explore...