Personally, I don't know why Herbstreit fires up so many people (especially around Columbus). He is literally just some guy, who happened to play quarterback, who now does media and has opinions. He is not the best commentator, but he is far from the worst.
I think Herbstreit has been trying to get out of a hole he dug for himself the past few years, mostly regarding his Ohio State commentary. His commentary on Ohio State football was in some measures accurate and apropos (we were mistaken as an "elite" program near the end of the Tressel years), but he doesn't know how to deliver a message without coming off as inflamed or petty. I recall him going off on a tangent during a Gameday segment in 2009. The location was either BYU (for its game against TCU) or TCU (for its game against Utah). I remember TCU being involved in that particular rant, but it wasn't the only one. As Ohio State fans started to take umbrage, he was eager to leave the area and blame Ohio State fans and the community for his exit.
What irritates college football fans about Herbstreit is less what he believes and more how he goes about communicating it. Thus, it becomes as much about what Herbstreit says AND how he says it. Herbstreit has been doing this in one form or another since he graduated from Ohio State after the 1992 season. He still doesn't know how to present a point of contention that could update the viewer's prior beliefs while assuaging, and not provoking, a viewer who does have strong, narrow beliefs about something.
The only difference is that he's become a bigger commodity over the years. He's ESPN's golden boy. With increased exposure and a prominent place near the top of ESPN's college football food chain, he's in a bigger position than he was previously to piss off college football fans at large.
That's not to say I don't think he's improved over the years. I never used to care much for his intellect, but I see him improving on this. He says less about "making plays in space" and other cliches than he did previously. While he's improved (I think he's become quite sharp on the spot, actually), he's still not a brilliant analyst like Gary Danielson. He's as aggravating as Danielson, though in a different form.
Ohio State fans feel stronger about Herbstreit because we know him. We have a longer rap sheet of things he's said than most college football fans. The problem is still the same as it was five years ago. Herbstreit doesn't know how to communicate a reasonable point (e.g. "Ohio State is not an elite program", "the SEC should stop scheduling FCS teams and go to nine conference games", "Northern Illinois is a questionable at-large selection for the Orange Bowl") without appearing like he's speaking way over his head or just trying to provoke viewers who have strong biases.
Analysis is one-part knowing what to say and and another part knowing how to say it. Herbstreit comes off as compensating a lack of conviction (or, previously, insight) with a boastful or indignant tone. He's the on-location Mark May.
That he appears to have such thin skin probably doesn't help matters any.
I no longer carry a grudge against Herbstreit. I don't mind him. I think he could probably benefit from getting fans to learn how to not mind him, even if they disagree with him or have views that clash with his.