"Katniss sure doesn't have romantic feelings for Gale"

If that's your interpretation of the text, that is fine, but that is not some absolute truth, and you can definitely argue that Katniss does not have romantic feelings for Gale. If I only think of someone as a friend, I don't get nervous about seeing them for the first time after kissing someone else, like Katniss does in the Hunger Games. I don't think things like this:

For the first time, I reverse our positions in my head. I imagine watching Gale

volunteering to save Rory in the reaping, having him torn from my life, becoming some strange girl's lover to stay alive, and then coming home with her. Living next to her. Promising to marry her. The hatred I feel for him, for the phantom girl, for everything, is so real and immediate that it chokes me. Gale is mine. I am his. Anything else is unthinkable. Why did it take him being whipped within an inch of his life to see it?

​

“We used to sell her strawberries,” I say almost angrily. What am I angry about, though? Not that she has brought the medicine, surely. “She must have quite a taste for them,” says Haymitch. That's what nettles me. It's the implication that there's something going on between Gale and Madge. And I don't like it.

"Appearance-wise, yes, Gale's jealousy and pressuring Katniss to choose him would appear romantic to most people."

Jealousy and possessiveness aren't healthy ways for romantic feelings to manifest, but that doesn't change the fact that they are romantic feelings. Are you seriously arguing that Gale didn't have romantic feelings for Katniss? That he wasn't hoping Katniss would choose him over Peeta? Whether Gale went about his feelings the correct way is beside the point.