people who are deeply in need are very frugal at spending their money
This article gives some of the logic behind redistributing income this way: https://www.washingtonpost.com/news/wonk/wp/2015/04/14/where...
The rich save more than the poor, and the more they have, they more they'll save. Money that's being saved isn't being spent, which means less business for everyone from the dry cleaner on the corner to the owner of a five-star hotel. In turn, that means less work for everybody and a lethargic economy.
To be sure, banks can invest the money that the wealthy save, which can stimulate the economy as well. Yet many observers... are worried that as a global society, we've accumulated too much in the way of savings already.