This is the phone giving the user a message. It is assumed that the phone has some name by which it can refer to the user. In many Linux installs on what are essentially single-user computers (personal computers) /etc/passwd will have been configured with the user’s real name. But maybe not. When you install Linux you are free to enter a fake name. All good.
The example message was of course a joke. If Purism actually implemented this, I would assume a far more bland message, such as:
This message is getting long. Consider using an external keyboard or docking your phone.
And, like Clippy, users will want some way to disable such chirpy helpfulness.
Is that message helpful? Maybe. It is easy to kind of get flow and continue bashing away beyond the point of good UX. Some users may not even have thought of using an external keyboard and may not even know that such a thing as a dock exists. It is unfamiliar territory. It is certainly not something that I have ever done with my current crop of blackbox phones.