I feel I need to comment here as a former Fox Valley resident who is well connected with many around both programs.
1) SCN as a school still has a major chip of its shoulders as the "second" school in town, despite a much better recent record in most sports
2) #1 is amplifield by SCN reputation as the "rich" school; many fewer low-income student and much more white. This drives a rumor of being "soft"
3) SCN's booster organization is completely out of control and driving too many athletic decisions. I personally know 2 folks who coached at the varsity level who have recently left coaching at North because they didn't want to deal with the booster.
All three of these drive SCN's rep across the area as a disliked team. (the Duke or Notre Dame if you will). Is it fair? Maybe, maybe not. Some of their teams play chippier than other. probably, especially in football, baseball and lacrosse.
In fact, I would argue most of the bad blood between SCN and SCE probably comes more than lacrosse than football.
Just my 2 cents.
Interesting perspective and some points I hadn’t considered. Bad blood and rivalries do tend to go hand in hand. Bears v Packers. Sox v Cubs and so on. It’s not necessarily always a bad thing and it definitely makes the games a little more intense for the players and more exciting to watch for the fans. It can begin to go off the rails if the teams don’t have an underlying respect for each other. Hopefully, both STC schools won’t let it get too far out of hand.