congrats, man. having a kid will change your perspective. it's one thing to be idealistic, but we don't live in a utopia.
i think that real 'justice' is people receiving what they dish out. cruel and unusual crimes deserve cruel and unusual punishments.
my personal experience with domestic violence comes from seeing my parents fight violently (mother trying to beat up my dad) for years until their divorce when i was about 9 or 10. i had a scar on my chin when i was 7 from the tip of a kitchen knife breaking off and flying at me, from my mother trying to slash my dad and hitting the knife on the counter.
when i was 7, my 4-year old, cute-as-a-button cousin was battered to death by the baby sitter (who was obviously mentally deranged. but like so many others, you don't see the signs until they snap). i still remember looking at her in her small, white casket - she was the first dead person i'd ever seen.
my wife and i have supported/contributed to this non-profit organization for the past decade, that helps people who have experienced domestic violence, child abuse, sexual assault and intimate partner violence:
https://www.awbw.org/awbw/about_us.php
bring your child up with ideals, but also make sure they're aware of reality both within and outside their immediate environment.