It’s wrong because it’s inefficient and leaves the UBI recipient no better off. In San Francisco, as an example, rental rates track remarkably close to the after-tax first paycheck of the month for the median tech worker. Every year rents and salaries go up in lock step. At the end of the day only the landlords are wealthier.
If UBI were X per month, we would see rents go up by X very very quickly. This is just what happens when a real estate market is inefficient and supply constrained.
Land value tax punishes the underutilization of land, creating a reason for property owners to redevelop underutilized land and add more supply. It also creates an incentive for the average homeowner to be more amenable to extra housing, as that homeowner doesn’t want their taxes going up due to increased land value.
You can see this in practice in Texas vs California. Texas has very high properly taxes (2.5-3%) and reassesses annually. California taxes are closer to 1% and essentially locked at the purchase price of your home no matter how much if appreciates.
As a result, homeowners in Texas are a lot more supportive of new housing compared to those in California who almost universally oppose it.
Given you will have progressive taxes. Land lords will be paying for your UBI more than others would will be paying for it.
The idea is here is not to punish the rich. But it's more on the lines of ensuring every one has something to rely on if they don't have a job.