It is absolutely a reporter's job to ask any and every question he can think of, no matter someone's opinion about the question. A reporter should especially ask uncomfortable and/or "gotcha" questions. It's not the job to consider how it would make the subject feel to have to answer a particular question. Get the fuck out with that shit.
Aside from that, Gundy shouldn't be admired or given an attaboy for his behavior. He's a 55 year old adult that earns $7.5 million a year. That money is given with the accepted and understood responsibility to handle a question he might not like without resorting to personal attacks and threats. That's the minimum and he can't even do that. He's the second longest tenured coach in FBS, a job that is generally short-lived and ends in humiliation. He has experienced none of that. Outside a few years at Baylor and Maryland, his entire coaching career has been in Stillwater where he was already revered as a former star QB. He has zero excuse to act like a petulant child at a bowl game press conference. Zero.
I also disagree with the notion that OSU couldn't enjoy the same success they've had with a new HC. It's a brave new world and nobody knows how the table will look when the chairs settle. Uncouple from OU and stake their own claim. Lean into B12 rivalries with Tech, Baylor, TCU and Houston to keep recruiting Texas. Without tripping over their dick every year at Bedlam, there's absolutely no reason OSU can't be a cyclical playoff team, with any half-decent coach. Personally, the Bedlam dick tripping has always said to me that Gundy would never get over the hump and win a title. But OSU most certainly can.