>it was rape because it’s a gross imbalance of power
First of all - racism. Second of all, not true. Nami was a fully fledged member of the Arlong pirates with all the respect that authority that came comes with that position. In fact, you can say she actually had more power in the crew than the average foot soldier because of the value she provided. It goes without saying that Arlong would have taken her side in all disputes as she was forging his dream for him.
>he groomed her
Nope. Nami was a free agent for most of her time. What she saw however when she’d come back to Windmill Village is Arlong ruling over the town with an iron but fair webbed fist. These are traits that women like, you know. Not simping, training endlessly or acting like a child.
>she was a child
No proof he did anything while she was a child unless you’re trying to push an agenda and are likely racist.

Arlong? Nami’s first and best.