You’re asking for a fairy world. Most people in history haven’t owned the land they live on. Most people would simply not own property without mortgages and would pay rent to someone hindering their ability to save.
America is the exception. Rome had widespread White slavery. Some people owned their land, a lot of them rented. The model of the yeoman farmer, the homesteader, and eventually the homeowner are unique in history. There isn’t free land out west so a loan is how people are going to buy their property for the foreseeable future. 
Interest is needed because of the time value of money, and a zero interest government loan means the government will lose money, so I can only assume you are a money-printing enjoyer who lives in America and takes the fed for granted. Otherwise you would just pay for that with taxes lol.
There’s a lot that goes into these decisions, and it’s not that the banks aren’t exploitative, but banking is needed because money isn’t free and sometimes people need it now rather than later.
You intuitively understand why a business loan is fair, you probably get why a mortgage is fair same for a car loan. It’s just bad optics to say, “the investment is worth the interest, the loan is good.” It’s not like people get dragged off to the salt mines when they can’t pay either, they just can’t borrow as much in the future, in America.
Now, is credit abused? Do institutions such as credit card companies incentivize it to be abused? Sure, but it’s like saying building an apartment with units to rent out is bad because in the 17th century Ukrainians lived on Polish lands paying rent to nobles they’d never see who used jews as middlemen to extract as much wealth as they could from them.