First, the wealth of the wealthy doesn't matter. If you have 10,000 dollars a year, then it's 10,000 whether the richest man has 50 billion or 150 Billion. The goal isn't to decrease their wealth, it's to increase yours. Even if you cut the wealth of the richest in half it won't increase your worth, especially in a Fiat Based Currency. It's like a kid who suddenly thinks his bike is worth less because he saw a kid with a shinier one.
Secondly, The wealthy have most of their money in things such as stocks and real estate. Typically when their wealth increases, it's from those sources, which is good, because it implies the value of those stocks and real estate have increased. When the wealthy get richer, it means the economy has improved.
But again I point out, how rich the richest are doesn't change the value of what the others have. 10k is 10k whether the other guy has 10billion or 100 billion. Decreasing their worth doesn't increase yours.