This is the second significant work stoppage in the past decade. The last one cost an entire season, the owners got everything they asked. If, a few years later, they need to re-open the agreement, they need to know that the fans aren't limitless with respect to forgiveness. Having an NHL game played to an empty arena makes that case clearly and concisely, and reduces to zero the chances they'll be this idiotic again.
Sports are only interesting to the degree that fans support them, people play them and take the time to watch and care about standings and games. By repeatedly showing disdain for the fan base, and for the sport itself, the league owners are clearly striking at the base of their own industry.