It is a very strange behavior directed towards people that leave an employer, for any reason. Prior to being hired and while working, the employee may be treated like family/friend, people seem genuinely friendly (more than just being a work colleague), but once the person leaves the company, they no longer exist or are basically scum, even when leaving on good terms.
This didn't just happen to me, but I noticed this behavior amongst coworkers at all of my jobs, when seeing people come and go or even when transferring within the company.
I'm not talking about the careful interactions for liability reasons. I understand they can no longer access confidential information, etc.
Example: an employee once left on good terms, everyone loved her, even HR and management. She had been there for 3 years and left the state for family reasons, even gave a 30 day notice. After her last day, she tried to call HR to ask questions about her last check and HR ignored her calls. She ended up emailing me and I asked HR, they said “she doesn't work here so I don't have to talk to her.” Wtf, just last week you guys were talking about how sad you are to see her go and that it will be hard finding a replacement! Not only that, our company has various retail stores, and all store staff were supposed to report to management any time that former employee were to come in to the store, as a customer (the person didn't even work in the store).
I have not only seen this at a recent job, but my previous employers as well and have seen it happen to me first hand. You're our family and we love you, until you leave (whether or not it's your choice) then we will hate you.
I have noticed this for about 10 years and just now decided to speak up about it because it's something I have never heard talked about. Please don't treat your ex employees like trash, you may end up working with/for them in the future… more importantly, just be a decent person.
TLDR; why are ex employees treated like shit even when they left on good terms?