The Forward quotes their leader this way:
“We are very much interested in the continued production of kosher meat,” said Rabbi Joel Meyers, executive vice president of the Conservative movement’s Rabbinical Assembly. “We just don’t want those plants that produce it to be perceived by the public as being somehow terrible.”
And what if those plants are terrible?
My guess: A whitewash. The Conservative rabbis are afraid their congregants will stop buying kosher meat or stop keeping kosher all together. So, in the name of “preserving” kashrut, they’ll let Rubashkin (largely) skate.
Also note the inordinate length of time it has taken for the Conservative rabbis to act. Plenty of time for Rubaskin to create a fig leaf of “respectability.”