The redskins are saying they haven't fired staff.
It's not stupid to keep them, for now. The players have to report to someone and day to day operations have to continue to function for a few more days (before everyone leaves.) So they have to stay on for at least the morning today to finish check ins, turning in of playbooks, etc.
The right thing to do was to remove Shanahan from position of power, bring in a GM (or promote from within) to start a coaching staff. Pick a coach. Then let him make decisions about his coaching staff (maybe he'll keep some, maybe not, let him decide)
It could also be Snyder giving them an FU by keeping them under contact as long as possible to hurt their chances of getting a job elsewhere.
It's unfortunate that I'm not sure what the actual reasoning is. I'm inclined to think Snyder is taking the petty route rather than the smart one.