You are right. It was a bad thing to do. But to post that it was an abandoned 4H project and/or a show rabbit is, as the lawyers would say, assuming facts not in evidence. The only thing you know for sure is that the rabbit was born in a rabbitry of some sort. The most probable thing that...
If you found it by the road how do you know it was a 4H show rabbit? It could have been a pet that was intentionally released or one that accidentally got out. I am curious how you came to the conclusion it was a show rabbit.
The person who suggested running an ad on Craigslist is the best idea and really the only solution for your dilemma.
Euthanizing them is just plain silly. Wasteful, too. Turning them loose is inhumane and probably illegal. The person who suggested running an ad on Craigslist had the best idea...