a "Linux user" is seen as noteworthy? What the heck?
I disagree with you and think it IS noteworthy, and of special interest to the Slashdot audience.
Many CEOs appear more like lawyers or salesmen/women. They may be very smart, but don't strike me as technical minded.
Running 4 different distributions of Linux implies a fair bit of technical knowledge, more than Windows and Mac usage. I find that I use more console commands in Linux than the other operating systems, and to know those commands requires reading man pages or other documentation, something that the average user may not do.
Each distribution of Linux can have different configuration commands and nuances. You may know how to configure the sound card on one distribution but another distribution can be totally different.
Linux comes pre-installed on only a few PCs, and I am going to assume the four systems didn't come with Linux. Most of the time you have to install and often configure it which is (and lets be honest) can be more difficult than Windows or Mac OS.
The bottom line is I don't know of many CEO type people that use Linux at home. I don't think the CEO of my company could do anything productive with Linux without significant help from technical staff, much less install and configure it at home for personal use.
I think the CEO candidate of a Linux company using Linux at home is noteworthy, relevant, and interesting.