Votes can be easily reversed so I don't see that as a problem. The real problem was the potential damage to the reputation of Steem of having a post that was giving off a very pungent whiff of plagiarism sit on top of the trending page. Action needed to be taken immediately. The onus is on the content creator to provide assurance that their content is original. If it is not original content adequate referencing needs to be provided. Neither was done is this case. It is also the responsibility of the content creator to monitor comments.