Just some advice but I'd like to kindly ask you to stop responding to trolls as telling them to stop only really feeds them since they are not going to stop merely by telling them to. It technically violates the UTP to feed the trolls so yeah.
He created a blog explaining it, that Mental Skillness deleted for... questionable reasons. You can read a transcript here. In reality, he left for several other reasons (including in an attempt to escape demotion), but you can read his given reasons in the blog transcript.
This is not vandalizing. It seems in all likelihood to me that it was just a bad edit made by a very new user. It did need to be reverted, but it was not vandalism. As they say on Wikipedia and Fandom, assume good faith. I just wanted to let you know.