The term is used to describe a temporary situation... The Big Three used to "lay off" workers for days or weeks at a time when production needed a break.
HPE employees who are given a WFR aren't welcome back ever. They are basically fired. They can't come back to work as a regular employee or a contractor. The most certainly are NOT laid off.
Conversely, if you decide to toss the shackles aside and go work elsewhere on your own accord, HPE goes out of its way to let you know they'll welcome you back. This seems a bit strange to me.