I think Hody's flashback was unnecessary, uncalled for, ridiculously and utterly stupid. It was really a bad move to do. The idea of Hody was that he is a monster bred from society's prejudice, and the fact that no human had ever harm (or tried to harm) him, emphasizes what he was. But now with this insertion, we know a human had tried to kidnap him before and Hody's rage is a bit more justifiable. I felt sympathy when that pirate tried to kidnap them, and soon realized that you weren't supposed to sympathize with Hody.
If the animators wanted to show why he revered Arlong so much, they can just portray Arlong coming back from wherever he's been and telling them all this stories about human scums. Though I know it probably (hopefully) won't affect much of the story or the characterization, I still can't get that bitter taste in my tongue after seeing this episode