The court was engaging in word games in order to set up a straw man. The clear meaning of the quoted statement (and other, similar, statements during the ratification debate) was to establish a minimum standard of state protection of "privileges and immunities" (i.e. they had to cover at least the same ground as Amendments I-VIII of the federal Constitution). This is not the same thing as a complete transfer of the entire issue from state to federal jurisidction, just as the establishment of minimum standards for business conduct (i.e. prohibitions of fraud, breach of contract, etc) are not the same thing as government micromanagement.
The Supreme Court, the Congress and the ratifying states didn't appear to agree.