To paraphrase what I understand.
She said, "Un-Pennsylvanian....un-American."
He asked, "What do you mean 'un-Pennsylvanion and un-American?"
She states, "I didn't say that."
He replies, "Yes you did. What excactely did you mean?"
She retorts, "I didn't say that. Shove it."
I seems that he was simply asking for clarification of what she meant. I don't find the reporter out of line by repeatedly asking what she meant by what she had just said.
I do find her response out of line along with all the people that are defending her and attacking (e-mail, vulgar language on the street, vulgar phone calls) the reporter.
[edit] If she didn't want to discuss what "un-etc" meant then could have simply could have told him, "No comment" and moved on. To deny having said something that she had just said seems a little kooky IMO