Can you be suspended/fired for a VOA post?

For context, this guy left a comment criticizing upper management and ended the comment saying, “Deny, Defend, Depose”. Now he posted he’s waiting for an email about said post. He was complaining that upper management was saying the weather wasn’t bad (sr op checked hours before it snowed and temps dropped) and that Amazon didn’t care for their employees or something along those lines. I can’t find the comment anymore since it’s probably deleted and there’s a lot of posts complaining