I mean...yeah. but the fact most japanese writers still find justifications to make the MCs participate in slavery, while making the relationship with those characters somehow develop around the subservience said slavery often pushes onto them... it just becomes worrying after seeing it repeat so many times.
NGL I do think authors take a few too many liberties with slavery. Especially when children are involved. All to often slavery is used as a crutch. A method to quickly integrate their character into their new environment, or as a mascot for the audience to fawn over or rally around. No quicker way for an MC to farm aura then to save a cute moeblob from a sick and grotesque environment. Bonus points if she turns into a cute natural disaster that drags the MC into all manner of awkward situations.
That being said, i do feel some forms of Slavery are justified and even required. Namely I think lawfully convicted criminals should be confined against their will and in meny cases forced to complete meaningful restitution as part of their punishment. And that restitution should scale harshly with crimes that contained unprovoked violence or egregious suffering on part of their victims.
While true this is one of those slippery slopes, I see a failure here is one of regulations from the governing body not the prison system.