No Don, not ad hominem.  

“Ad hominem (Latin for "to the man" or "to the person"[1]), short for argumentum ad hominem, is a logical fallacy in which an argument is rebutted by attacking the character, motive, or other attribute of the person making the argument, or persons associated with the argument, rather than attacking the substance of the argument itself.[2]” - https://en.wikipedia.org/wiki/Ad_hominem

I was not attacking your character or motive. I was pointing out that the substance of your comment was plagiarized. Your comment, consisting of 13 words, copied 10 of those words verbatim from the writing of Paul Simon. Without attribution. Plagiarism is stealing, Don. I try to point it out whenever I see it.

On the other hand Don, your reply to my comment was “ad hominem”. You completely ignored the substance of my comment (your plagiarism) and suggested that I had some ulterior motive for making the comment.