Having been a reader of EW for quite some time, I think I can say with certainty that EW's definition of a cult show is one with a very loyal following but without a huge following. And it doesn't matter to them if the show is currently on the air (like CHUCK, SUPERNATURAL, DOCTOR WHO, etc.) or has been off the air for decades (like BEAUTY AND THE BEAST, POLICE SQUAD, THE PRISONER, etc.). The shows on that list would fit that profile. And now that I think about it, that could explain why ST isn't on the list...