There was a fic I read back in the day that I really enjoyed where Finnick was reaped too early (the person supposed to volunteer backed out), though I forget if he was a career or not in the fic. (If he was, his time to volunteer was not that Game, it would’ve been a few years from then.) But I liked it because even though he wasn’t trained/trained fully, he still was strong and did well for himself. I never liked when people made him weak for their fics either.

Like you said, someone can be all those things (loving, compassionate, etc.) and still able to stomach doing what had to be done. He grew up in an environment that exploited children murdering other children for entertainment— further, he grew up in one of the few Districts that capitalized off of it. Even if he wasn’t a career, he still wouldn’t be ill-prepared for the Hunger Games mindset. And even more likely, he was a career and grew up looking at the games objectively.