Others have explained the basics--the scum sucking sleazoid wrongfully accused BD of cheating--but that's not all of it for me. As explained in the article Native linked, others have done the same. What's different about the scum sucking sleazoid is that he (a) actively promoted this garbage among the coaching ranks (which is very likely why Montgomery said what he did), (b) got others to make accusations (especially the scum sucking sleazoid's mini me, Fogler) as well, and (c) unlike Montgomery, has never apologized for the harm he did.

Calling into question someone else's integrity with NO FACTS to back you up is one of the lowest things a coach can do. BD is about as squeaky clean as he could be and he works harder than just about any other coach. Having his integrity questioned, especially by someone he had respected so, was a huge blow to him. I will never forgive the scum sucking sleazoid for what he did to my coach. It's way, way too late for an apology now. If I ever meet the sleazebucket in person, he will get an ear full and, if I thought I could get away with it, a swift kick in the junk.