At the risk of feeding a troll... no, that is not the proposal. The proposal is to make it economically unviable to do socially suboptimal things with common resources.
The underlying principle is that land - including natural resources as a whole - is finite. It's a common good owned by humanity as a whole; or, failing that, at least in common by the nation-state in which it falls. Allowing individuals to hoard those finite resources is bad for society.
Under a land-value tax system, individuals can do whatever they want, but they're appropriately charged for their negative externalities. Just like we should have a carbon tax to disincentivize people using the shared natural resource of carbon fixing without a good reason, we should have a land tax to disincentivize people using the shared natural resource of flat, arable land without a good reason. You can choose to pay your taxes and do nothing with the land, if you have another source of wealth to make up for it - effectively, you need to express to society just how much it's worth it to you to sit on that land doing nothing, and the way that we express the strength of our convictions in a market economy is with dollars.
> There's also something very objectionable about attempting to use taxation as a tool to manipulate behavior and engineer outcomes.
The goal here is not to manipulate behavior for its own sake, it's to use the power of the state to correct for a mispricing in the market. Market forces alone are incapable of correctly pricing deals involving common goods, because most of the people who are implicitly participating in the transaction (i.e., the rest of humanity that is now deprived of that land/air/resource) are not compensated. It's a problem of negative externalities, for which a Pigouvian tax [1] is a perfectly appropriate remedy. In a democracy, the state is how the public as a whole imposes its collective will; having the state "bid" on behalf of the public interest is the most capitalist solution possible to the externalities problem.
[1] https://en.wikipedia.org/wiki/Pigouvian_tax