Ok, well, I think that's a ludicrous position to take, and your views on this topic are unreasonable. All taxes are "completely arbitrary" in some sense. They're the result of compromises, political and economic pressures, and expressions of the values of a society.
I agree with the parent comment that estates in excess of some amount (maybe one or two million dollars, inflation-indexed) should be taxed at an extremely high rate to discourage the development of aristocratic dynasties.
Then you need to mature your point of view because the world isn't so absurdly simple and black and white.
No thinking person can look at this country (U.S.) today and say accumulated wealth isn't causing a whole host of problems. The wealth inequality in this country is bad and needs to be addressed. The rich are out of control.
And without all that wealth accumulation, the financial markets wouldn't be rigged. They were rigged by the wealthy buying politicians to get the laws they like passed. The markets are a symptom of the problem, they aren't the problem itself; accumulated wealth is the problem.
The distinction between inheritances and other forms of income in tax treatment is at least as arbitrary. If we tax income in general, why should income from inheritances be treated specially?
Consider: There may be other alternatives that fall between the extremes of "My kids get all the free money I can give them!" and "The government should confiscate all possessions and give everyone a state-sponsored apartment."