@Desperado:
Maybe hatesink is too harsh, but Oda emphasizes repeatedly over the series how little regard he has for traditional families and biological relationships.
Why is showing nice relationships outside of the usual ones showing "little regard" for usual ones. You're talking like its some either/or choice that it isn't. Oda's shown strong blood family and strong adopted family in equal amounts.
All main characters growing up without their parents who are either dead, abusive, negligent or too busy following their dreams and no one gives a damn.
How does showing mothers or fathers as dead express a negative opinion of blood relationships lol. Otherwise though are you sure? Luffy we don't know yet anything about his parental relationships aside from not knowing his father. Zoro we know NOTHING about. Nami is a war orphan, so her parents are likely dead. Usopp actually had a good relationship with his mom and EVEN his absentee father even if that's kind of eyebrow raising. Robin's dad was dead and her mom she was shown bonding with before she died. Brooke we know nothing about. So really only Sanji and Chopper (lol) fit what you're saying of negative portrayal of blood relations in the main cast.
Big Mom who has hordes of children who have fragile allegiance to her just so she can use them to further her political influence.
That's a VERY traditional family system.
Fishman island is presented as an utopia because biology goes completely random and siblings barely have anything in common with each other.
Fishman island was not presented as a utopia. And this is completely aside from what you're saying. Those Fishman don't share traits, but they do share blood. Those ARE biological relationships. How alike they look to each-other is irrelevant.
Foster families (Bellmere, Zeff, Whitebeard, Ace/Sabo/Luffy etc.) are presented almost always in an overly positive light even if they are evil (Doffy).
Adopted parents are not foster parents. Those are two different things. Only Dadan and her bandits really fit the mold of foster parents. And in what sense are they overly positive? Oda shows the rough edges of how confusing and sensitive the lack of blood ties is in Nami's family. Zeff and Sanji have a very very rough relationship that they don't even get honest about until the VERY end of Sanji's time on Baratie, and he still really hasn't directly admitted that he thinks of Zeff as his father. And the Doflamingo family was not shown very positively, though the characterization of Doffy and company in that arc was insanely messy so sometimes it was, then sometimes it wasn't.
Not even the nobles care about biology and freely exchange children they deem unfit.
We saw this only happened once ever, and it was done in an emergency situation where the noble family thought they no longer had a son to pass their dynasty down with.What even is your point anyway with all this?