The Founders understood that relatively free markets are the most effective form of social organization for promoting individual freedom. Indeed, capitalism is defined as a system wherein individuals are free to pursue their own interests, make voluntary exchanges, and hold private property rights in goods and services. Much of the original intent of the United States Constitution, as seen in the document itself and in the Federalist Papers that advocated its ratification, was to bring about a climate in which this kind of social organization could occur. In a free society, most relationships should be voluntary, and involuntary exchange should be minimized. Widespread private control and ownership of property is consistent with this objective.
Government is the major source of forced exchanges, the most prominent of which is taxation.
Anything that weakens the institution of private property interferes with the attainment of the socially desirable outcomes just described. Taxes represent government claims on private property. As taxes rise, you own less and less of what you earn. If the tax rate were ever to reach 100 percent, the government would have destroyed private property, and you would own none of what you had earned. Keep in mind that a working definition of slavery is that you work but do not have any rights to the fruit of your labor.