Taxing people because they have more than you is called stealing.
Mixing up terms doesn't help the discussion. Stealing is when someone takes something of yours without permission. Taxes are one of the ways we pay for common necessities.
When you're dead, the stuff isn't yours any more. :-)
Why should investment income or capital gains be taxed differently than wages? Why do some places tax property less when the owner is over 65? Why does marital status impact the taxes we pay? Why do churches not pay taxes? Why aren't we allowed to withhold a portion of our taxes for things we disagree with? Because our representatives have written the rules that way. There are fairness arguments on both sides.
For me it comes down to the things I've discussed many times before. Our government requires money for the services we demand (or demanded in the past). Accumulation of vast sums of wealth based on inheritance is bad for society if it goes on too long. It makes more sense for the wealthy to pay more (a higher percentage) than the poor and lower middle class. It makes sense for estates to be taxed when they change hands when they are large enough.
Cheers,
Scott.