The red icon stands for red, or red in the form of a red button. It’s a red button on a red background and it represents a red button that was once used as a button, only now it stands for red.
The red icon is an obvious way to bring up the concept of “red as a color and color as a symbol of power.” Red is the color of power, the color of “The Force” in the Star Wars world. In the Star Wars universe, the color red is associated with the dark side, with Jedi, and Darth Vader. The red icon itself is a symbol of power, hence the red color.