why does satan despise humans and desire their destruction?

Answer 1

Satan was created as an angel to serve God. It was after he rebelled that Men were created in the image of God. Satan was not created in the image of God, but wanted to be God.

Since looking a men reminded him of God, and the fact that men had more "spiritual authority" than he did, Satan tried and was successful in interfering with God's plan for man (fellowship).

After Jesus (a man) was raised from the dead, Satan realized how big of a mistake he made by killing Jesus.

Now, when he looks at people that are saved, he sees Jesus too.