All organisms including bacteria and fungi feed on dead animals and plants. Then why is it that only bacteria and fungi are called decomposers?

Bacteria  and fungi play an important role in the decomposition process. They are responsible for breaking down the organisms that are decaying.They chemically breakdown dead organisms and change them from complex organic substances to simple inorganic substances that mix with the soil, to obtain energy for themselves. As their 'decompose ' waste and leave no residue, they are called decomposers.