We're talking about your sphere with a top and bottom.
Any 90 degree angle taken from a radial will be sloped not horizontal.
Every point on that line will be above or below the others.
You agreed earlier that horizontal can't be sloped.
Spheres do not have a top and bottom. If you take a basketball and hold it up you will say that it has a top and bottom. However, if you rotate the sphere top to bottom 180°, then the top has become the bottom and the bottom has become the top. So what what does "top" and "bottom" really mean?
Remember, the Earth is really REALLY big and because of that, it has a gravity that always pulls things towards its center. Wherever you go on Earth, down is defined by gravity pulling you towards the center if the planet at that point.