Those scenes were to show how the mc doesnt feel empathy. Cuz hes human, he understands life is fleeting, but as a vampire he doesn't really care abt that. He cares more that his purpose for living is disappearing, and if he cant protect that kid then hes useless.
But since he found a way to kill blue bloods, his purpose in life came back. As a human u might see that as unforgivable, but for a vamp thats the same as losing an ant u were responsible for.

Bro just killed a child there's no romance after that there's no coming back from that and there's no forgiveness like wtaf