These are two bad defenses. St. Francis gave up 80 points in its last game. Fairleigh Dickinson yielded 95 points in its past game. That may have influenced the oddsmaker because this total is set too high even given the low quality of the defenses.
St. Francis has been held to 70 or fewer points in regulation during eight of its last 10 games. The Under is 9-3 in its last 12 road matchups. 
As for Fairleigh Dickinson, yes the Knights surrendered 95 points to Wagner in their last game. But in their previous three games, the Knights gave up an average of 69.3 points. That was against Wagner and two games versus Long Island, both of which have above average offenses.