This is your self-defense that has become a common practice by other plagiarists.
Don't really understand why people ignored this issue before you and one other person were accepted into the bestchange campaign, but it's true that you made a huge mistake based on forum rules.
This is way overboard IMO. The post in question seems to be referencing the copied text as "smuggled out snippet below" so arguably Mpamaegbu was not trying to claim authorship of that text.