Re: Beginners with delusions of grandeur...
You did the right thing, kept your cool, didn't retaliate, Etc.
Next stop should have been sensei. Not to get the new guy in trouble, but so Sensei would see the need to explain why and how we train.
Your problem with the new student (who evidently is finally catching on) was that he failed to understand that he was simulating a fast and strong attack, though moving slowly for safety. Had he really come fast and had your thrown fast, he would not have been able to twist out of anything. You know this. If he wouldn't listen to you, Sensei needed to remind everyone of the rules.
This sort of nonsense goes on way too often. Beginners just don't understand the meaning of ukemi or the reasons that we practice the way we do. Sometimes experiences students will take advantage of the slow practice and kindness of Nage because they want to demonstrate their (imagined) superiority by refusing to follow in their ukemi. If Sensei doesn't call them on it, it will continue.