Why would an employee in uniform want to be around people who are not from the airline? I would personally have a hard time being in an AC with my uniform on. Employees have their own lounges while working. Employee lounges are great escapes from dealing with people. I would think the AC would be a difficult place to "chill out".
Now if im out of uniform and a guest that would be different.

And employees are not allowed access to just "chill" especially while in uniform. I have often wondered what the clubs look like though