Public projects and services cost a lot of money. Raising that money is the primary purpose of taxes.
This basic fact has been somewhat obfuscated in the past few decades during which we’ve all learned to regard taxes as a tool to deter certain behaviors (you pay taxes on the tobacco you smoke), and encourage others (you get a tax break on a part of the revenue you save for retirement).
Rich people often wield that view to fend off higher tax rates, claiming that it would “unfairly punish the people that did well.”
Once established the material (as opposed to moral) basis for taxes, comes another common anti-wealth-tax argument: “why should rich people pay more for the services that everyone use?”
It’s true that rich people tend to use public transit much less than poor people. They send their kids to private schools for which they pay out of their own pockets, and seldom use public libraries.
However, the same can’t be said of those they employ. To expand their fortune, the rich rely on the labor of the majority of the population. This labor has an immediate cost—the workers’ salaries—but it also comes with many indirect costs. For example, children take the school bus, freeing parents to take their own bus to work while the kids learn skills for their future jobs.