@inthehands His stated reason was that Hawaii has a high proportion of federal employees.
The scuttlebutt on the hill is apparently that he got all the same fury everyone else was getting, but he has the fewest constituents, so he agreed to inflate the yea count as a favor to Schumer and Durbin. In exchange for ??? of course. But considering how much flak even the nays are going to get, he may well come to regret it.