It seems like it was a DMCA takedown request. Anyone can submit these to content hosters and the hoster has to follow the process, which typically means removing the content until it can be proven that it isnt violating copyright. The problem isn’t the takedown request, but that it was given to itch.io’s registrar instead of itch.io itself. It’d be like asking to takedown youtube from the web because someone reposted your video on it.