Also, if they still had Genesis they could have shot one on Praxis instead of discussing a 10-year plan of rescue and evacuation of the Klingon planet, which supposedly is inevitably doomed.
But that was not life or death. There was other options. Ones much more benificial to the federation, plus the klingons held a dim view of Genesis. If the Feds used one it might re ignite the fear the federation would use it as a WMD against them.
With the borg the situation is diffrent. Lossing means death for all be it Klingon, Romulan, Cardassian or Breen! Anything to stop the borg should be on the table.