1a. You encourage them to die, and provide an "ethical" means of suicide

1b. You actively set about eliminating them

We have many examples of genocide from the last century alone for reasons far more petty than the wealthy protecting their hoard. The ultra wealthy are naturally at odds with the interests of the public, and if they have the support of the military, don't even have to pretend to care (e.g. Myanmar).

Couple that with innovations military automatons, and the ultra wealthy may be faced with a choice between living like God Emperors in a world denuded of most human life or having to share their wealth to prevent a second Reign of Terror.