While I agree that nothing excuses three separate instances, in the future, you will find it much better to handle these things behind the scenes. I'm inferring that your dismissal from the guild was due to unnecessary drama in guild threads. Most guilds will not tolerate this, as public bickering and fighting have been the demise of many guilds. From a leadership standpoint, the other player was breaking rules, but it was containable. However, your behavior was far worse for the guild as a whole.
In the future, it is best to handle these things privately with leaders. I've had an ongoing problem with a specific guildmate in one world. I have been talking it over with the founder for weeks. I had already warned two leaders that I was likely to go off on them if they didn't get him under control. The behavior occurred again the other day, and I let the guildmate have it- through a private message. His response was to tattle, and I informed him that I've been in discussion already for weeks, so he could go ahead and talk to leadership. I put him on ignore (first time I've ever done that to a guildmate, but as I said, this has been brewing and I did not want it to escalate further.) Leaders opened a new thread with all of the leaders, plus myself and said guildmate. Guildmate was then educated in the matter. I would have preferred they remove him from the guild, but all of the leaders were working with him to prevent the problem from happening again. If it does, it will be a him or me ultimatum. I can't imagine them choosing him, but if they do, I will put my big-girl pants on and find a new guild.