Over the past 40 years, all petitions generated by the states for a convention have been from conservatives. First it was to reverse "One Man/One Vote" for the apportionment of state legislatures. Then it was for a balanced budget amendment. Then it was to reverse Roe. So far the liberals have not managed to generate petitions from the states for their pet causes. This may have something to do with the fact that liberals are uncomfortable with federalism, i.e. states' rights.
The point of the essay is to make clear that a Convention for Proposing Amendments has the same proposal rights as Congress. You don't fear Congress "messing" with the Constitution, do you? Congress has the right to "mess" with it every day.
A convention is the way the states can get around congressional intransigence to propose an amendment on a subject. No more, no less.
If we are going to re-institute slavery, I've got dibs on you.