I see nothing wrong with this. I think it's good to be specific. The Linux implementation is different from many other containerization solutions (eg, Solaris Zones, AIX WPAR, HPUX partitions, etc, so forth). The scope of "all container solutions for every platform" is too broad to be able to provide much depth, and the audience of people interested in container information for all platforms instead of a specific platform is fairly narrow.

There's plenty of room for someone to make a document specific to other platforms for a different audience. There's even room for someone to make a comparison of all platforms. It depends on your goal, your knowledge, and your intended audience.