The number #1 reason to hate the Spirit of Mammon is that he is unrighteous. This means that he is the opposite of God who is all righteousness. This means that Jehovah God sets the standard for what righteousness really is. So He is not just righteous He is the very definition of what is righteous and righteousness. Thus why the Bible tells us in Matthew 6:46 that in order to love God will Hate Mammon. You cannot serve Right and Wrong. And although we may try according to that same verse it's impossible.
This creates a situation where you may feel as though you're doing the right thing when all actuality your not. It is possible to think that you love God when in all actuality you love Mammon the god of money. Just take a look at the story of the rich young ruler in the Bible in Mathew 19:16-22 kjv. He asked Jesus what he could do to obtain eternal life. Jesus ran down a shortlist of things and the rich young ruler replied in verse 20 “All these things I have kept from my youth. What do I still lack?” When Jesus said great then there is only one thing left that you need to do. Go and sell what you have and give it to the poor and come and follow me. But he could not do it because the Bible records that his possessions were great and that he could not bring himself to part with them.
This was a test to see not whether our not he was a sinner because he said he kept the covenants and had not sinned all his life. But it was a test to see who his Master was Jehovah God creator and destroyer of his soul or Mammon god of money and wealth. Obviously, in this story, Mammon won. But because it was Jesus Christ the Son of the Living God who told him what he needed to do to be saved we can safely deduct that because of his disobedience his soul was eternally lost. That's of course unless he repented. Whenever we do what Mammon/money wants us to do by default we become unrighteous because mammon is God's opposite.
Now, by you being a Child, Son or Daughter of God, Mammon has a natural hatred for you. Being the god of money this means he uses his rulership to keep you broke. That's right Mammon desires to see you penniless. It is impossible for him to like you even in the least bit. Therefore because he is God's opposite in order to love God we must hate Mammon. The Biblical absolute is found in Mathew Chapter 6:24.
"No one can serve two masters; for either he will hate the one and love the other, or else he will be loyal to the one and despise the other. You cannot serve God and mammon."
To be righteous we must hate everything that is unrighteous. There is no way around this.