The people on my team who were let go were always respectful, but did voice their opinions. They stood up for us all and our members and will be gone now. Good leaders should value that, especially as these folks were solid or excellent performers. What seemed to characterize then though, is the fact that they would stand up and make their thoughts known. I got the impression that they were considered an annoyance to my coach, who is a bit incompetent if I am to be honest, and a very negative, bad-cop type "leader".
I have noticed this as well. It certainly seems to send a clear message - keep your head down, or you'll be shown the door. I hope this is just a coincidence, but I highly doubt it.