Does anyone else find it weird when they romanticize jealousy? If my partner wanted to control me to the point that I couldn't be around friends I would run. I get that they're in the awkward "I wonder if they like me too" phase and his jealousy is a sign that 'yes, he likes you." There are signs and there are red flags.
Perhaps it's like alcohol. A little gets you buzzed, and a lot gets you dead // A little jealousy is the dark side of love, a lot of jealousy is a violent crime.
Yeah, I usually find it off-putting if it's a controlling kind of jealousy. I think you got it right, here, where for Hinata, who's worried that she's beyond romantic consideration because he sees her as a sister/daughter/whatever, the idea of him feeling THAT kind of jealousy eliminates a lot of those possibilities and gives her a lot to hope or. I like that her reaction is less "smug satisfaction" and more "wide-eyed, gears turning," suggesting that she's not into the jealousy itself, but what it implies. "In order to have me all to himself, first he'd have to have me... he wants to have me?"
And in defense of his jealousy in this instance, the text goes above and beyond in riddling the classmate's beach invitation with obvious signs that this dude is not her friend, but a threatening fuckboy who wants to take advantage of her - she barely remembers his name, but he's blatantly staring at her tits, acting way too familiar, isolating her from Asahi and getting touchy to ask her a second time, and immediately flirting with others girls while Asahi and Hinako are walking away.
Ironically, they set up a "jealousy excludes dad/brother feelings" situation where dads and brothers would absolutely be like "never, ever be alone with that guy."