They are talking about OTA channels that play sporting events.
ABC, NBC, CBS, Fox all broadcast live sporting events of some sort.
To me that doesn't mean the free over the air channels that occasionally show sports. But hey, that's me.
I can't imagine I'm the only one. Sports is pretty much the only thing I can't get from iTunes or streaming.
I assume everybody wants all of them in all markets, it's just a different strategy of when to make something available. E.g. what if you're like me, and primarily watch college sports on ESPN, and don't really care about NBC or Fox locals in your market?
Honestly it's painful at this point watching regular tv when my internet goes down. It seems like Plex should still work in that case though.
Of course some cableTV providers (Time-Warner/Spectrum in particular) mark every program with CCI 0x02 "copy-once" DRM, and very few DVRs other than TiVo and Windows Media Center (RIP) allow you to record that due to standard cable company evil.
(I heard that's part of why Microsoft dropped CableCard support in Windows 10 because the cable companies decided to not-so-quietly kill it and have made it almost impossible to get them if you don't already have one and have been slowly dropping support even for those that already have them.)
Edit: I just saw their Supported DVR Devices and Antennas web page[1] and ATI isn't listed :(