Unix abandoned (or never had) any conception of WYSIWYG, and probably never will. I hate it, too.
In this case, the complaint is that what you've got can't be represented by what you see. There are a couple of ways to approximately display what you see, but they're approximations. (One is wrap and the other is "off the edge of the screen".)
In a WYSIWYG, you can't represent a line longer than the screen width. This is a problem when lines matter.
That's why WYSIWYG is more accurately called "What You See Is All You Have".