>For the instances where individual molecules are charged, why do they never form ionic bonds as a result of being charged?

They actually do in many cases. For example, a molecule like acetic acid can lose a H+ ion to become acetate, which has a negative charge, and it can form ionic bonds with sodium to form sodium acetate crystals. In these crystals, negatively charged oxygen atoms from the acetate ion are ionically bonded to the positively charged sodium ions. Different crystal structures can form depending on how much water is present.

Isolated pairs of ions don't tend to stay associated in this manner for a variety of reasons (at least in the condensed phase such as an aqueous solution), but as long as they can form a regular lattice with the right energetics, molecules are perfectly capable of forming ionic bonds.