No it wasn't. You were causing harm to another persons belongings. Imagine this: You go become friends with a random stranger, he lets you in his house and you burn it down. Tell the court system it was just a joke and that you saved the guys dog! Again, you're a friend and deserve to stay banned.
Virtual legos aren't considered property, that is the worst comparison I have ever seen. Badspot banned him because it says in the EULA that he can ban you for any reason at any time, and he thought he deserved to be banned, that is all there is to it. Nothing illegal happened.