If we make the same analysis with light, we will realize that this fact will also occur. We know that the light emitted is formed by electric and magnetic fields, in this way, a light source emits light in all directions. As a result, electric and magnetic fields are also produced in all directions, always being perpendicular to the direction of propagation.
Therefore, we can say that light is polarized when it passes through the polarizer propagating in a single direction.
If we place another crystal, after the first polarizing crystal, whose polarizing slits are perpendicular to the direction of propagation of the previously polarized light, we will see that these waves will not cross the crystal. In this way we say that polarization is a property of transverse waves.