It was a minor anecdotal comment based on my own experience of hiring/managing employees. Maybe I'm a crap manager but I've always found it labourious to get rid of people (especially passed the 2-year mark as you say). I may as well add that my wife has worked in HR for coming up to 15 years as well and I've been privy to all sorts of juicy legal drama via her.
I generally try and give every response to me some consideration but I'm not sure what else to say. Seems like maybe you just wanted to use my comment as a segway into your point about the erosion of employee protections, which you're entitled to do of course.