If I worked in a place with this type of banter being constant I would consider it a hostile workplace.
For me, the fact that they both dish it and can take it, and the fact it is very public and condoned by the station, leads me to believe that they do not consider what they are doing to be hostile. Like I said, in my workplace, I do not consider "digs" to be hostile at all. They aren't true digs. We don't really mean what we are saying, and everyone knows it. When someone says, "Well, you would think that, you Harvard snob!" (with a laugh and wink) during a department meeting, he doesn't really think Harvard people or the particular lawyer is a snob. It's a joke. It's not serious or malicious.