In other words, it would look really bad for the church to fund BYU athletics to people who are concerned about how their tithing dollars are used.

A few examples:
1. I was in a gospel doctrine class a few years back and someone asked the softball question: "How do you feel when you see the temple?" and after the typical answers, one sister said, "I feel sick because I think of all the money that was spent on such a beautiful temple, that could have been given to the poor." Now I know this is an extreme example and this sister is incorrect, and that 99% of the members support things like temples and chapels, but imagine how many more members would say the same thing when you are talking about funding BYU athletics.

2. Look at how strongly people feel about how their tax dollars are wasted. Republicans are upset that their tax dollars go to pay for welfare and food stamps for people who are lazy or on drugs, and abortions for anyone. Democrats get upset that their tax dollars are used to bail out greedy corporations and to fight wars they don't support. (I'm not saying either of those points are true, but that is the impression and hence these are used as examples by each party of government corruption). Of course the big difference is that taxes are required by law; tithing is not. So how many people would say, "I'm not paying my tithing, it goes to buy crab legs for BYU football players! Look at what a waste!" In the US I think that the backlash would be less, but can you imagine in some of the poorer countries? Try explaining to a poor member from Mozambique who probably pays $100 in tithing a year how their tithing can pay for one new change of uniforms for a BYU football player. It just doesn't look good.

While I disagree with these sentiments and think that the church uses tithing for lots of things it considers "investments" because they are for the good of the church, the difference is here that the optics are very poor so I doubt this will ever happen.