At that moment, there was no more use for them, they'd LOST their jobs - Unemployed.
And it was probably like when we lost our jobs when I worked at Enron long ago. Most were nearly in tears, some were high-fiving. Those that high-fived weren't being idiots - it was just a last "team hurrah". Maybe inappropriate in a larger context, but to them, it's they way they expressed appreciation for having been a part of it. And I've seen plenty of misfits that just aren't sensitive or aware that their personal reaction just isn't the best thing to do at the time.
I just do not see it as a Harley worker gloating.