Because at the end of the day, those sports have a ton of student-athletes, most of which are paying a bunch of money in tuition because the NCAA doesn't allocate a lot of scholarships for those sports, and former student-athletes tend to be your more active and passionate alumni.I have always had the question of what value does fielding a men's and women's golf/tennis/swimming/gymnastics/fencing team provide to any school? I see no benefit to the school fielding non-revenue generating sports with the exception of the possibility of a few more meaningless trophies in the hallway that no one cares about.
Mens and womens golf, tennis, swimming, gymnastics, and fencing combine to lose about $4M a year, and their rosters combine to have over 200 student-athletes - and, given the nature of those sports and the specialized (read: expensive) training that's required to get to the D1 level, you can wager a guess that most of those 200 student-athletes are students who come from a little bit of money. Those sports are actually pretty efficient when it comes to a "dollars spent per student athlete" perspective. Even moreso when you consider that most of the co-ed sports share the same coaching staff.
Women's basketball, to use an example, loses more money by itself ($5M) than all of the above-referenced sports combined. Women's volleyball loses $1.5M a year to support a roster of 16.