I was there last night and I really enjoyed all the Huskers fans I talked to. I didn't see a single thing that I would consider a negative interaction between UW and Neb fans. A little trash-talking? Sure, but nothing that wasn't in the spirit of fun. And it was generally followed by respectful and serious talk about the game, the teams, the campuses, etc. And to be honest, I always asked them how they were enjoying the trip, and no one had a bad word to say. About Madison and the people hear anyway. About the Huskers is a different story.
Yes, UW students have vulgar chants. They've been a tradition for decades now. Those of us who go every week just kind of roll our eyes and ignore it. And as others already said, it's all internally directed and has nothing to do with opposing fans. It's a remnant of the days when the Badgers sucked and students had to entertain themselves during the game. It became tradition. There's been efforts to rein it in over the years, with the predictable effect of increasing it. And if you were there, the ES-FU, over-rated etc chants were entirely confined to the student section.
I've never gone to a road game in the Big Ten or a bowl and not run across some. I'm absolutely sure I'll run across some if I head down to Lincoln next year. But it's a little silly to judge an entire fan base of 80,000 on one or two anecdotes.