Isalm-berg? Seriously? Oxy-moran!
If you read the OPM guidance, the people being RIF'd have rights - the right to 30 days notice of RIF, the right to contest their position being RIF'd, etc..
The law may allow POTUS to do a Blunt Force RIF, but he'd likely lose a lawsuit by the union and the workers because he could have given 30-day notice, and didn't.