If you were an actual paying customer for those lounges, why in the world would you want employees sitting around you. You'd get one of 2 things.
1. The class of an airline employee does not match the class of the people in those lounges, which seems to be the case here.
2. The paying passengers go in there to get away from complaining whining people, toss a FA or pilot in there and you just loss that.

That guy that wrote the article in the usa today last year hit it dead on. The guys piece was about how he sits in the airport and can't get away from airline employees complaining no matter where he sits. He went on to say if you don't like your job then quit.

Before you say "maybe he should stop buying the cheap ticket" Remember its your company that sets those prices (the prices on price line, etc. are also on the company site)

Or before you say if I got paid more I wouldn't complain (yes we would, what else can we talk about for 4 days) remember you took the job knowing how bad it was.

I personally agree that employees shouldn't be allowed to mingle with the customers, its not good business. One disgruntled employee in those lounges can cost the company a lot of money.

PS, before someone says company man. I despise Delta, Barely have ever like any company I have worked for, and the only reason I like my new job is because I'm new again.