Here's why:

* Lack of Carbon-Carbon Bonds: Inorganic compounds generally lack complex carbon skeletons. While methane does contain carbon, it doesn't have carbon-carbon bonds.

* Simple Structure: Inorganic compounds often have relatively simple structures compared to organic compounds. Methane's structure is straightforward, with one carbon atom bonded to four hydrogen atoms.

* Traditionally Inorganic: Methane is primarily found in natural gas, a source often associated with inorganic materials.

While methane is a very simple molecule, it's important to remember that the line between organic and inorganic chemistry can be blurry. Some compounds defy easy categorization.