A tort based on what? If there no legal standard of "extra virgin", then everything can be extra virgin. You have no bases upon which to build a tort claim.
"What gives the FedGov the lawful power to regulate that?"
The Commerce Clause, or so held the Supreme Court in a number of challenges to the The 1938 Food, Drug, and Cosmetic Act.
This is the flaw in many FReepers otherwise conservative thinking. What is "extra virgin" olive oil?
You never need to know. Mavens study the issue (look up "mavens" and see how important they are to commerce and liberty) and then you can investigate it if it is important to you.
Otherwise it really isn't an issue. If widespread fraud is occurring and extra virgin means nothing, then consumers will react correctly.
You cannot correct for every flaw and some torts are beneath notice.