There is nothing BYU can do about that. If BYU always ends up hiring coaches that end up leaving for Duke, Kentucky, UNC, etc. I would be thrilled. To get hired at schools like that, you have to be a great coach. I would rather have great coaches that leave than one mediocre coach that sticks around.
On a personal level, I have no issue with Pope. Anyone in his position would make the same decision. There is no reason not to root for his success. It will not harm BYU if Pope does well. 95% of the time the players that Kentucky goes after are not ones that would even consider going to BYU.