Because Oda does it sensibly, and isn't just "WHUTE MAN BAD."
Look at Arlong and Hordi Jones.
Arlong is basically the biggest Racist in the series and while he is given a contextual reason to hate Humans..at no point does anyone say that Arlong's actions were justified because of Humanities Racism against him. Hordi Jones had a scene where he outright admitted that for his whining about being "Oppressed" by Humans, he had never actually experienced it personally.
or Kiku, the actual Trans character in the series, She isn't treated like the center of her universe, and there is more to the character than being Trans.
Shit the overarching Myth Arc has become incredibly timely in the past couple of years because it is about a Totalitarian Government Deciding what people are Allowed to know and actively attacking anyone who doesn't fall in line with censorship.
I don't think I would call Oda political at all really, I just think he is a Normie who has Normie takes like "Totalitarianism is Bad, Racism is Bad, Slavery is bad, Censorship is Bad". Remember most of the "Woke" people in the world are complete Retards who have no actual idea what their Ideology actually means.