The professor in question has a pretty thorough explanation of why he thinks the request is problematic (
Abusing Open Records to Attack Academic Freedom | Scholar as Citizen). He seems reasonable to me and it seems like the decision to comply is out of his hands. The Wisconsin Republican Party's response is classic: they accused him of attempting to intimidate them. Apparently, the big old meany history professor wrote a big old mean blog full of mean old context and the Republican Party got intimidated.
Though I guess I'm not surprised that a hyperpartisan political organization would be intimidated by the prospect of the rational weighing of facts.