Here's why:

* Atomic Structure: Sulfur atoms have a strong hold on their electrons, making them reluctant to easily move and carry an electrical current. This is due to sulfur's position in the periodic table as a nonmetal and its high electronegativity.

* Lack of Free Electrons: Unlike metals which have a "sea" of free electrons, sulfur has very few free electrons. This makes it difficult for electricity to flow through it.

* Insulating Properties: Sulfur is actually a good insulator, meaning it resists the flow of electricity. This property is used in various applications, like electrical insulation in transformers and high-voltage equipment.

In summary, sulfur's atomic structure and lack of free electrons make it a poor conductor of electricity.