Justify it however you want, but you are committing a crime.
Grand theft is a felony crime in the United States defined as the theft of objects exceeding a certain monetary value. Grand theft is committed when the money, labor, real or personal property stolen is valued at more than $400. Grand Theft can be charged as a misdemeanor or felony and is punishable by up to one year in county jail or 16 months in state prison, depending on the value of the goods stolen.
If your bank accidentally deposited $10,000 into your bank account, and you knew it was not yours, would you go out and spend it right away? Or would you call the bank and ask them about it to make matters right?
You, and the people that agree you should keep it have no conscience. You live in a world of "everything is owed to you".