If I worked at a place like that, I'd sure as hell work my butt of to get a job somewhere else.

Or in my case, actively ignore any and all recruiting from that sesspool.

If someone quits their job, do all their opinions suddenly become suspect? You're kind of damned-if-you-do-damned-if-you-don't. Either you work for the company and you are biased one way, or you quit and now your bias is now suddenly the other way. I've joined and quit many jobs and my opinion may or may not have changed due to my change in status but it is clearly and ad hominem attack.

Not the OP, but:

The point was not that their opinion is suspect, the point was that they are former because people who care about the customer get fired and/or that everyone who cared is former, so nobody who is left cares.