They are fine with an employee being tired during the day due to their own personal projects but are not fine with being tired due to a second employment? What difference does that make? That's just stupid.
They're not fine with an employee being tired due to their own side-projects, if you were underperforming you'd get told off by your manager, asked to improve e.t.c. all the way to getting fired.
You being able to own the IP to things you create outside of work does not mean that you suddenly don't have to work during your actual work times.
Also, if an employer gave that as a reason for them keeping my IP created outside of work hours I would very seriously reconsider accepting a job with them (other reasons such as those outlined in Joel's article make a lot of sense).
What you are saying is not within the context of what I was replying to. The comment specifically stated that they ensure you are not tired by not allowing you to be employed by a third-party, and yet personal projects are fine in that context.
Unless the comment I was responding to was worded badly, my statement is valid.
