According to coinmarketcap your altcoin ranks at 448, and has a market cap of only $4.1MM.

Your thread has ~1800 pages of posts, while the ANN thread for etherum has ~1150 pages, but etherum is much more well known, and there are dozens, if not hundreds (if not thousands) of projects built on top of etherum. I am not sure how this can be accounted for except for shilling, which is certainly not something good for the forum.

With the above being said, I don't support banning people for plagiarism that happened a long time ago, and in only "small" amounts, when they are otherwise not breaking any rules. There isn't any other rule in which no warnings are given (perhaps no warning is necessary in most cases, but maybe a 60 day ban would be more appropriate as a final warning would be more appropriate if someone is caught plagiarizing, when a high ranking account is involved). It doesn't seem right to me to be removing people from the forum willy-nilly who are currently contributing to the forum. 

With the above being said, there is an argument you should be banned for bump spam. This obviously relies on the speculation that you have many shills supporting your altcoin.