It's all a scam. I'm convinced that people listing these units are like those who put their 50m2 crackden in Dock Sud for sale for 300K just to placate some family member who wants them to sell the unit, i.e. they put a price nobody with any sense would pay for, renting or purchasing, to say to their spouse/family "see, I listed it."
The minimum wage in CABA is $130/month, and the average is closer to $350. These people are choosing to keep the units empty.