Originally Posted by Vinayaka

The monotheism in Hinduism is different than the monotheism in western faiths. One way to explain the difference is inclusive versus exclusive. In western faiths, God is exclusive. There is only one God, and no others. In other words it excludes all other gods. In Hinduism, there is one Supreme God and also other gods, so it's called inclusive monotheism.

The idea that other Gods are just aspects or traits of God is a Vedanta concept, and Vedanta is most certainly a school of Hinduism, and the one most likely to be found in the west. But there are also other schools with other views. For example, I see Ganesha as distinct from Siva, standing on his own, more like an archangel, although that doesn't quite explain it either. Maybe 'really big archangel' would be better.