The ownership of the team is currently divided among the Rooneys. Dan (Chairman) and his 5 sons...with Art II (team President), are the owners. Some of the brothers have interests in gambling operations...and gambling and sports are "no mix" situations as far as the NFL is concerned. Those brothers are looking to sell their interest in the team.

This article describes it better than I can:
http://www.postgazette.com/pg/08192/896048-66.stm

I think the main thing is that NOBODY, including the bothers that are trying to sell their interests, wants to "ruin" the Rooney/Steeler legacy and reputation...