Yup or really not able to read thing littlerly her father told Luffy not to make her cry if that doesn't scream out as a romance hint. Then I don't know what does.
I think it makes for good headcanon, but romance? That's just not what the arc was about. Arlong had tormented Nami for much of her life, had murdered her mother in front of her and had more or less forced her to behave in a fashion she despised. We see the emotional crescendo of all of this when Arlong double crosses her by stealing the money she had gotten and she's kneeling on the ground slicing her own arm. Luffy walks up to her, not having any idea about what's going on nor even bothering to ask, but doesn't hesitate to help her when she asks him. He doesn't need to know the details of Nami's wretched life or what she's had to go through. To him, it's simple: She's his nakama. It's a great scene because it showcases Luffy's character, which though simple, is very profound.
Now one could definitely take this scene and use it as a means of expounding upon headcanon and perhaps even writer a great fanfic (I've seen many), but objectively? Nami crying, Luffy being told not to make her cry, Luffy kicking Arlong's ass and destroying all of the maps Nami made? Romance just wasn't Oda's point. Not trying to bash your fandom; power to you. I'm just being as objective as possible.
He also doesn't like it she cries in fact he goes ballistic on the guy who makes her cry.
This is the extent to which he is willing to go for the bond he shares with his nakama. Recall what Luffy did the minute he found out what Frankie House did to Usopp. He stormed down there no differently than he had at Arlong and him, Zoro and Sanji kicked some serious ass. Recall what Luffy did when Robin was taken in by CP9. He declared war on the entire World government without any hesitation. Recall the way Luffy acted when Kuma sent all of the crew members to different islands. He went ballistic, thinking he had lost them all.
It'd be one thing if Nami were Luffy's only crewmate. Then, I might consider your interpretation. But when you've got him consistently acting that way to protect each and every one of his crewmates, I can't even conceive the thought that Oda is trying to hint romance here.
Cough or the way he says pervy things when she put water on herself like those swim suits models.
This one, I don't specifically recall at the moment. I do remember a similar case in Alabasta when Luffy and Ussop did nosebleed at Nami's happiness punch, but Oda explained that one as him just acting that way around Usopp due his bad influence.
Yeah Luffy no we are just seeing things lol.
It happens. I've made that mistake many times before (back when Avatar was still a thing, I was convinced Katara and Zuko would get together based on similar vague evidence).