The cartoon kids might be kicking because they're trying to show off their skills or competing with each other. Or perhaps they're responding to something that happened in the story.
Perhaps the cartoon is trying to show that the legs are unable to kick due to a lack of strength or motivation. It could also be a part of a comical or absurd scene where normal physical actions don't follow the usual rules.
Well, it might depend on the storyline and the animation quality. If it's well-written and visually appealing, it could be a hit. But if the plot is weak or the animation is poor, it might not be so great.
The popularity could be due to several factors. Firstly, they might evoke nostalgia for a certain era. Secondly, the well-choreographed kicking scenes can be visually appealing and engaging. Also, they could offer a break from more common cartoon themes.
It could be that the cartoon cat sees the chickens as a threat or it's part of a comical scene. But it's all fictional and not based on any real logic.