What happens when something already owned grows in value past the arbitrary maximum? Net worth is, after all, a function of how valuable everyone else thinks the stuff you own is. It’s a price tag.
If you buy a rookie baseball card for $5, and he has a great year and now your card is worth $100, did you deprive anyone of $95 by continuing to own it?
The premise that merely having more than you need is inherently unethical is completely arbitrary, doubly so when only applied to those who have the most.
I live a fairly simple and frugal lifestyle. The amount of money where I am living at the standard of living and want, and my “savings are enough to ride out life in comfort”, is likely a much lower number than most others in the US.
Does that make me more ethical than those others? I don’t believe so.