I don't think you can just categorically blame the alumni. Even in your example, if your university had similar athletic department financial mismanagement and hockey was (due to internal budget meetings) slated for the ax, the hockey donor would only have saved this sport, and may have had to provide a greater donation to fund the program in addition to constructing the new facility, and most likely chip in for all the care and maintenance to keep it going, since his facility would now become a new potential issue the athletic department would have to manage in relation to other ongoing problems they have failed to adequately fund.
From what I remember, the U of Maryland athletic department was just completely mismanaged, and the answer was to cut 8 non-revenue sports to balance the budget. Do you really think men's cross country, water polo, or tennis alumni were following the inner workings of the greater athletic department financial woes to proactively avoid this extreme decision the university came up with?
I don't think any alumnus is that tuned in to how an annual donation to the varsity club, athletic department, or university is specifically earmarked. Correct me if I'm wrong, but even if you donate to a specific team via athletic department or varsity club annual drives, we don't really know how it is administered, e.g., each team's annual percentage allocated to general athletic department programs it utilizes, etc.