Meaning that their living expenses were subsidized by their parents.
Yes, such costs are typically much lower than living in the college dorm, but they are not $0, and students who do not have the option of living with their parents (e.g. the parents live in a remote area too far to reasonably commute to college from) or whose parents are unwilling to let them live there will not have such an option (much less in a subsidized form).