If someone feels that an editor has been editing disruptively, it is perfectly in order for them to report it to administrators to consider whether any action should be taken. It is a matter of courtesy to warn the user in advance that doing so is being considered, and to give the editor a chance to stop. In fact, a report to administrators is likely to be simply dismissed if no warning has been given first. I do think that more friendly wording might have been used, rather than  "I will report you to Wikipedia admins and have you blocked", but I have seen far more uncivil warnings than that. The IP editor has just given you that one message since your last edit to the article, and, since you say that you are "done with" the article, it may be that he/she will leave it at that. If the IP editor persists in posting to you about it after you have stopped editing the article, then please come back and tell me, as that may well be harassment, and action may well be needed, but if what has happened so far is the end of it, then I don't see any reason for not just letting it drop.