Well, suit yourself. Unless someone is not interested in creating games with Copper Cube 6, then you can ignore the message, but any rational person would use it to create their own game and publish it, even market it commercially and to be frank there is nothing you will be able to do, because you don't copyright your material, someone uses this and they won't be accused of stealing, because you put it out in the open for free. In the end, someone can end up with profit from your work. That's your choice I guess, volunteering and charity is great, I agree.
Edit: Best of luck with future games.
Thank you for your wishes!
I have always been a fan of John Camark and have always followed his open-source game ideas. And for a small developer like me, it's already an honor for me to have someone really interested in my game. I don't care what they do with my game, otherwise I wouldn't have released it for free. I'm just a middle school student now, and games are just one of my hobbies. Being able to have someone play can already fulfill my small wish, that's all.
Once again, thank you from the bottom of my heart!