The difference is, no one tried to re-write history when Afro Samurai was written. It was always considered as fiction from A to Z, and no one said "By the way, he was a real samurai".
However, they tried and keep trying to push Yasuke as a real samurai, even the official AC website says "Yasuke, the powerful African samurai of historical legend.". They are straight up trying to re-write history, and this is where it stops being a purely fictional story.
And still, to this day, no one can say what Yasuke's last name was. All samurais had last name.
The difference is, no one tried to re-write history when Afro Samurai was written. It was always considered as fiction from A to Z, and no one said "By the way, he was a real samurai".
However, they tried and keep trying to push Yasuke as a real samurai, even the official AC website says "Yasuke, the powerful African samurai of historical legend.". They are straight up trying to re-write history, and this is where it stops being a purely fictional story.
And still, to this day, no one can say what Yasuke's last name was. All samurais had last name.