I've read or heard a couple of theories on this bandied about. It was suggested on EWTN's coverage of the Dallas USCCB meeting that "the bishops are afraid." Now, what did this mean? Are they afraid of the pressure from homosexual activist groups? Afraid Dignity and "Act Up" people would disrupt Masses, as they have in New York in the past? Or "afraid" that homosexual priests would stage protests or leave in large numbers? It's unclear.
The other possibility is that some bishops who do support banning homosexuals from the priesthood were afraid that trying to address that now would detract from clearing up the ephebophile and pedophile abuse mess. In other words, the protests and unrest unleashed by speaking negatively of homosexuals would just drown out all other discussion. Hard to say.
They are going to have to take a hard look at the "elephant in the room" at some point. All you have to do is ask - "What is the charter protecting children from?" The answer? Being sodomized by homosexual priests.
An ugly suggestion, but how many of them might be afraid of being outed?