Yes, there's nothing else we can do but getting over it and starting all over again.
It sounds like your students were treated unfairly, but maybe this is a teaching opportunity. Even if treated unfairly, they can choose how to react. Even if protesting through channels might not lead to change, it's worth fighting on their behalf and showing them they're worth it, and how to conduct themselves.
Bigger picture: Outside rewards are nice, but there's a lot of worth in knowing that you worked hard and did your best, and hopefully had some fun while doing it. And they can always opt to work even harder and excel. That's a good lesson to learn, especially while young. Resiliency is something that serves us well throughout life, and helps feed success long term. Being treated unfairly also helps teach empathy. If the adults around them make the most of this experience, the kids can learn more than they ever could've by just winning a trophy.
I had jobs earlier when I encountered immature co-workers and bad bosses, for instance, and I ended up learning more -- about how not to behave and how to manage effectively -- than I ever would've in better circumstances. Those experiences helped me succeed down the road, and I'm very appreciative that I got the opportunities, in retrospect.
When bad things happen, people who are mature have the opportunity to set an example, and kids can learn from that, even if they don't realize it.