COMPRESSION makes sense cause like how if two tectonic plates collide they will cause a peak such as this mountain. Shearing would not work because shearing is like if two people walk past each other they don’t even collide they just pass each other. Or take for example if you cut a sandwich in half and move one of the two halves up and the other one down (north to south) that is shearing. While compression is if you mash the sandwiches together east to west.
