I think it had to do with the number of 20 year old players on their roster.
https://www.telegraphherald.com/sports/local_sports/article_31c8a926-6298-4731-acd0-2d2e0f139308.html
They didn't remodel it. It was torn down and rebuilt in sections and it's not quite finished yet. The Moorhead sports center and one gymnasium are the only things left from the old school. I know some politicians were pushing for a second school.