If you want to dig for a reason why kids like Rots. They're kids. It's that simple. When they become smarter, they'll see it for what it is I guess. I used to love power rangers and grew out of that. They'll grow out of rots.
As for older fans who love rots, I blame Nostalgia. It's the most nostalgic prequel movie for me, since it has the emperor, vader, luke, leia, chewie. it's almost an ot movie except for it being so badly written.