Even in legal matters if the plagiarism is not exceeding a % it is not counted as plagiarism.Else the whole youtube could be called plagiarism and be sued to death.
Go tagg him for plagiarism and create your next enemy.
You are digging your own grave.
I'll keep watching
Also i would recommend to read the definition of plagiarism.
Its a high % copy of something.
If the creator created the banner himself and only used part of somebodies idea that is not plagiarism.
If i read something and write it down in my own words this is also not plagiarism even some words will match and the main message will be the same