Why would this young couple want to "buy" a home, instead of renting one?
And even if they want it, why should the state encourge that?

In the US renting appartments is very common (mostly because people move around alot). My parents lived in a rented appartment, with me and my 6 siblings. So did all of my friends, and we were a quite normal middle class family.

Why is buying an appartment is such a must?