Well, it probably depends on which software's concern will be implementing a policy to prevent users from having permission to fill critical directories and pre

Well, it probably depends on which software's concern will be implementing a policy to prevent users from having permission to fill critical directories and prevent the system from operating normally, which is discussed in the article. Which is also a coordination problem because the most common user of disk is software itself, I think. FHS seems to specifically imbue the user with the responsibility and consequences of filling up the disk.