The advice is different than I would have given. Having the same idea as someone isn't copying them. If someone points out to you that they wrote something similar, you could reply "hey thanks I hadn't see that" and add a note mentioning it to your own thing if it seems relevant. Or, especially if you're being accused, you could just ignore them as an internet crank.
Trying to debate them, as the author suggests, seems like the worst possible idea to me. What is possibly going to come of that?