Oda wrote a lot of morally good Kings.
Kings of a country can be corrupt, but generally, they can and should focus their intentions on helping their country
but a global institution, like the world government is essentially inherently corrupt, especially with a single King standing over it, just being decadent and unfair by design.
There´s honestly no story purpose for making Blackbeards ancestor, who could clearly be the inspiration for all the evil pirates into a good guy








