I imagine it's because your anatomy is actually more suited to dropping a log while popping a squat. Because of this many people will keep a stepping stool in front of their toilet to put their feet on while sitting on the toilet. It can make doing your business easier, especially if you're constipated
Okay it's a pooping step, I'm aware of those. But why is it blue?! I guess the source image was probably a thing about pooping steps. So it was originally blue to draw attention to it. Well it worked!
