This is a good illustration of how tone doesn't come across well in writing. Reading the comment by the original author, it sounded like a friendly request to please take the content down. The guy whose site it was clearly didn't see it that way and responded as though he'd been viscously attacked. He ends up coming across as quite angry, when more likely he was just rattled and feeling defensive. I guess the takeawa…
With that said, such situations are exactly the sort that mildly unfriendly requests are appropriate for. I did the same thing when someone took my BSD licensed code, replaced my name in the copyright notice with his own, and put it up on github. Fundamentally, you're not making a request, you're giving a command.