I don't think Herbstriet has anything against Nebraska. The two instances I've seen as examples:
- 2016 - from the point where he was kind of laughing, we went 2-4 the rest of the year. So, while I wouldn't have laughed, even as a huge Neb supporter, I didn't think we would stay ranked that high and it turns out he was completely right.
- All-time greats show - The way I heard the story, was that the producers saw the Neb fans were overwhelming the voting process so the show was turning into an all-Neb discussion. In his earpiece - they said to do / say something interesting or controversial to keep the thing going and to keep the national audience. He very easily could have been grasping at straws to be a contrarian just to give them something / anything to talk about.
I think in general, Herbstriet is a straight shooter - the biggest issue is that there hasn't been much for him to celebrate with Nebraska with regards to the national stage.
When that changes, I am confident that he will be one of the first in line to recognize that.