Google "straw man" - I never proposed a progressive taxation system so need not defend one.
If you have no interest in taxing a millionaire at a higher rate than you do his janitor, then we agree.
I would not tax either of them a penny on their wealth or income. The one with more property will pay more tax and if it happens to be the millionaire, he will reduce the wage he pays his janitor. Call it trickle down taxation.
The important thing is that both are encouraged to employ their assets and there is no penalty for success.
If you are only taxing those who own property, then you're intentionally pushing people into renting rather than ownership.
And since the government owns 28% of the land in the U.S. - that's 28% that will never be taxed.