Nails, we're, stones, what about all of them, where do they go? Does the cow control where or what stomach/ compartment is used or body knows and makes it happen?
The video is not strictly wrong. Steel is an alloy made of several metals including iron which is magnetic. However you are not wrong either. Some steels use allotrope of iron which is nonmagnetic. So it would be more correct to say "some" steel is magnetic.
centripetal force is a real force that acts inward to keep objects in circular motion, while centrifugal force is the apparent outward force experienced by objects in circular motion due to their inertia