To answer I’ll put your question in another perspective. Say you have $20 and I have $10. Why isn’t it simply “right” for me to steal $5 from you, so we’re even? Your question ignores the fluctuations in the economy. Classes aren’t fixed, at least not in a Capitalist system. The “1%” or “the rich” changes all the time, and if their companies fail they may end up bankrupt and in enormous debt. In these cases its about earning the money. Though you’ve earned it, your proposition is that since I have less I have the right to that money. I wouldn’t have earned it, so why should I demand it? Another thing is, what if we had a redistribution of wealth which sought equity as a final goal? Inequality would soon again become the result of every pay check. Why? Because some people save, some invest and others spend. The reason I may have had $10 when confronting you may have been because I just bought a product for $20, which would total to me having more than you had. So in following the mindset of equity as an ideal goal, I wouldn’t have had to pay you, but rather the opposite, to secure equity. In this way, saving is discouraged, and spending is encouraged, and we’re left with an economy based on wealth destruction rather than production. Total societal wealth isn’t fixed.
In your other case, you ask about inherited wealth. But what makes it “right” for the state to seize the money, as opposed to the inheritor? It presupposes that the state by default has the authority and ownership over that wealth – and over all wealth – and that they should be in the position to redistribute as they see fit. A question which may be raised is who deserves the dead person’s wealth? That’s by no means a simple question to answer. Why should the state have the “right” to that money? The same question may be asked about the kids of the deceased. Here the default is (at least in most countries I know) that the wealth goes to the children. And often it is the will of the parent that it should do so, except when he gives it away to someone else in a testimony. In psychology and philosophy, it has been proposed that the meaning in life when one becomes old is what one has accomplished, and that his efforts and legacy will continue through his children. Why exactly this is the attitude is not the subject of the debate right now, but taking it at face value, isn’t the state doing a “wrong” rather than “right”, as it’s exploiting the accomplishments of the deceased. Does the ends really justify the means in this regard? If the possessor says that his property and wealth should go to X, what gives the state the right to say, “no, we’d rather have it be given to Y.”