Being knocked out of the NCAA tournament by losing four straight and going 1-5 on the season against the conference's newest program doesn't go over very well in the hockey state.
http://www.uscho.com/2018/03/20/report-lucia-out-at-minnesota-after-19-seasons-behind-the-bench/
Hockey is now big money in big ten. No room for a storied program losing
Hockey has always been a big deal in the land of a thousand lakes. They invented hockey (or at least believe they did), don't you know. They think they should win a championship every year. Lucia hadn't won a National Championship in a long time, came in fifth in the conference this year, was swept out of the conference tournament by the 2nd newest program in college hockey, and lost their NCAA bid to an in-state rival (Minnesota-Duluth). If they had tied or won one more game, they would have made the tournament, but as a three-seed. None of that goes over well up north.
Here's a couple more articles from College Hockey News explaining the situation in college hockey.
Here's what the departing coach (Don Lucia) had to say:
https://www.collegehockeynews.com/news/2018/03/21_Don-Lucia-Reflects-on-37.php
And an article on the competitive nature and unrealistic expectations of the fans:
https://www.collegehockeynews.com/news/2018/03/21_Lucia,-Minnesota,-and-Coupon.php