There hasn't been a gun confiscation law that Giuliani didn't absolutely LOVE. He bragged, as mayor of NYC, about how many thousands of guns that HE had confiscated. And then when the first attack from an islamic terrorist hit NYC while he was mayor he took that opportunity to gather gun-grabbing liberal Democrats together and to call for more gun laws to include supporting Bill Clinton's efforts for national gun control.
The bottom line is that he purposely took guns away from New Yorkers, making them unable to defend themselves against violent criminals. And for those New Yorkers who died because of his efforts to take their guns away, Giuliani has their blood on his hands.