Why don't viruses have the same structure as the five kingdoms?

Viruses are not considered to belong to any of the five kingdoms of life (animalia, plantae, fungi, protista, and monera) because they lack the characteristics of cells such as organelles, cellular structure, and metabolism. Viruses are considered acellular as they are composed of genetic material (DNA or RNA) surrounded by a protein coat, and they require a host cell to replicate.