What I find really weird is I have a website, or had a website years ago, that someone issued a DMCA takedown to it, but it was totally fraudulent. The registrar sent me an email to say they had received the takedown request, had reviewed it, found it to be invalid, and we're taking no further action.

They didn't send me this email until after they'd already decided to ignore the report. Start to finish the whole thing took about 3 days. That was for some tiny irrelevant website that no one except me and a few users would have even cared if it had been taken down. Why didn't they do the same for a massive internationally well-known website?