Reason I'm asking is because I have an aunt that owns like maybe 3 - 5 (not sure the exact amount) small townhouses around the city (well, when I say "city" think of like the areas around a city where theres no tall buildings, but only small 2-3 stories single family homes in the neighborhood) and have these houses up for rent, and honestly, my aunt and her husband doesn't seem like a terrible people. They still work a normal job, and have to pay taxes like everyone else have to. They still have their own debts to pay. I'm not sure exactly how, but my parents say they did a combination of saving up money and taking loans from banks to be able to buy these properties, fix them, then put them up for rent. They don't overcharge, and usually charge slightly below the market to retain tenants, and fix things (or hire people to fix things) when their tenants request them.
I mean, they are just trying to survive in this capitalistic world. They wanna save up for retirement, and fund their kids to college, and leave something for their kids, so they have less of stress in life. I don't see them as bad people. I mean, its not like they own multiple apartment buildings, or doing excessive wealth hoarding.
Do leftists mean people like my aunt too? Or are they an exception to the "landlords are bad" sentinment?
This describes any financial transaction in a capitalist system.
No it does not. If I pay you to build a water desalinating machine then suddenly we'll have an abundance of fresh water. We've increased the available supply of drinking water overall.
Similarly building more housing is not as morally bankrupt as buying up existing housing and renting it back out at a profit. If you actually build more housing, you are providing a service; if you only get paid for the hours you work, you only make a reasonable amount of money, and you do a good job, you might actually be net benefit to society as a whole, as you are increasing the available supply of housing for people.
On the other hand when you live in a city where there is a limited supply of housing and you buy that up and rent it back to people at a profit so that you don't have to work, you are simply draining the system of resources.
There is a reason that economists literally use the term 'rent-seeking' to describe behaviour that is personally profitable while draining the efficiency of the system as a whole, and not all types of businesses (and thus investment in them) are considered to be rent-seeking.