A rich person already pays taxes at a rate that is currently heavily influenced by rich people, so I'm not seeing that as much of a justification.

But yes, when a rich person gives their money to another person, that other person now has to pay tax. An estate, gift, or income tax.

Many rich people pay their employees, some don't; wage theft is very popular, as are other forms of labor exploitation. But an educated, healthy, available labor force is a very expensive asset to create. We all invest in creating that through things like paying for schools, health care, and raising children. One of the ways we pay for creating that asset is taxes. Rich people, as the ones most benefiting from society, and also as the ones with the most spare money, should pay their fair share for that.