It isn't intended to punish success, per se. The intention is to limit the amount of power one person can amass as a result of the imperfect, unchecked functioning of the economic process.
Earlier this year, Jeff Bezos sold Amazon stock worth roughly $2.8 billion. That's $2.8 billion in liquid assets that are usable for any purpose. (Jeff Bezos still has about $100B in Amazon stock).
Assuming a person can, over the long run, safely earn 2% above inflation through a diversified investment portfolio, the cash from that sale alone provides Bezos with an annual budget of $50+ million in perpetuity for his own personal use and the use of his descendants, without him (or them) doing anything else productive ever. Amazon could collapse into nothingness, it wouldn't matter.
Those who advocate for restrictions on accumulated wealth (through a direct wealth tax as proposed by Elizabeth Warren, or through estate taxes which have been a more traditional route) believe that there shouldn't be this level of power concentrated in the hands of an individual that is so divorced from their continued efforts or value added to society.
In some frame of reference, this position could be seen as absurd. If we believe that every amount of money a person accumulates is a result of the value they add and the effort they undertook, then it can seem downright evil to take it away. If I spend 50 years toiling away on my own property to build a house for me and my descendants, why on earth should anyone be allowed to come take part of it??!?!
The problem though, is that the relationship between work >> value added >> wealth accumulated isn't always the same. You (probably), like me and most others, work and get paid for your effort on the basis of time (yearly, hourly, by the job, etc.). This relationship forms the basis for most people's intuition about the process.
Not so for the richest among us. You don't become rich through labor alone. You become rich through capital accumulation, which relies on leveraging, by implicit or explicit agreement, the labor of others. Here, the wealth you accumulate becomes a function of a more complex equation, and often the sorts of behaviors that maximize this accumulation are not as much about hard work / effort, and are not always related to value added.
In theory, a perfectly competitive environment in which we have perfect information and minimal market friction would only allocate the marginal increase in value to the business owner. In other words, Jeff Bezos would be worth only as much as the increase in the collective production of society as a result of Amazon existing.
We could theoretically determine that value by asking the question: If Amazon had never existed, what would the net impact on the economy be? Do we think there would be another online retailer (or a larger collection of retailers) performing a similar function? It is entirely possible we could be better off without Amazon.
This isn't to minimize the life Jeff Bezos devoted to founding and growing Amazon. Very few could rise to that point without hard work, dedication, and brilliance. But, I will say this: there are people who worked just as hard, were just as dedicated and brilliant, and whose efforts added more value to society who aren't billionaires or millionaires. Those who rise to that level of wealth generally do so as a result of market imperfections more so than as a result of their effort.
If one believes that accumulation of such wealth is more the product of imperfections in the free markets, then it follows naturally that they would advocate for societal mechanisms (like a wealth tax or estate tax) that reign in the consequences of those imperfections.