Larison has a theory:
When all of the major powers opposed to intervention abstained on the resolution, supporters of the war were encouraged by this, but those abstentions were really votes of no-confidence. Germany was as adamantly against the Libyan war as it was against the Iraq war, but this time the permanent member opponents were willing to let Western governments plunge ahead without a lengthy, protracted debate and the threat of veto in the Security Council. After all, why should they jeopardize their relations with Western governments by opposing the Westerners’ folly?
Brazil and Turkey have already experienced the unpleasant political consequences of trying to do the right thing by Western governments by opposing misguided Iran sanctions, and others probably learned from that episode that there is nothing to be gained by getting in between Western governments and their targets. Germany probably doesn’t want to repeat its Iraq war experience by damaging the relationship with the U.S. to save Obama from making a mistake.