Re: why it's a bad thing, buying a home in Baltimore is already relatively affordable compared to renting. That suggests that we need more rental homes, not more houses available for sale.

There are many reasons you want a robust rental market. Buying a house is not always better. The general rule of thumb is that you need to live in a house for seven years in order for the transactional costs to be worth it. Lots of people are not staying here for that long. Baltimore has a lot of grad students, medical residents, nurses working at big hospitals for the first few years of their careers and just people who don't want to stay in the city after having kids. People have become more mobile in general. If you want those mobile people to be part of your tax base for at least a few years then they need to have decent rental options.