There are different interpretations. This one is going off of the concept that items slaved to a host become icons on that host. Otherwise, for example, a host would be unable to perform control device actions on the devices slaved to it. Meaning the whole idea of hacking into a building's host to take control of the doors would be impossible.
I know that I'm not the only one who has come to that conclusion, as I didn't come up with it myself. And I'm not entirely certain I like that interpretation either. Personally, I liked the idea of having "Home Nodes" much better. The idea that each and every corporate building has its own host seems a little over-the-top.
I think, having a mid-range between commlinks/cyberdecks and Hosts would make more sense. Something that is more powerful than a commlink/cyberdeck (depending on quality) but isn't mobile would work fine. In 4th edition, they were called a nexus. They wouldn't have the complete autonomy of a host, but they would be something tied to a specific location. The Core rules contradict themselves in many ways, simultaneously saying that Hosts have no physical location but then saying that they could be tied to a physical location.
Sorry, went a little off-topic there...