While the entire scene that led to the kiss was incredibly awkward, it’s a common trope for characters to fall for someone after sharing some grand adventure or traumatic experience.
Also, regarding the slave kids, it’s pretty obvious why they didn’t attempt to save them in The Last Jedi, they were rushing to get back to a First Order command ship, and didn’t have time to find them a safe place on Canto Bight. That and the fact that they’d know where they were when they’d return for them…which they should have as Rian sat up several threads including an explicit manner in re-arming the Resistance and JJ stupidly abandoned them all along with Tico.
Plus, it’s nowhere near as bad as Qui-Gon leaving Shmi behind on Tatooine.
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