That's exactly the question I have for the rich. ;)

But no, seriously, that's the argument for wealth redistribution: the rich only are able to amass such wealth because of advantages they've accumulated for various reasons. If you're full-blown communist, it's due to the appropriation of the surplus labor produced by the proletariat. Therefore, you're just taking back what they took in the first place.

Now, you may disagree, but I figured since you asked, you might want an answer.