I'm not getting a clear idea from the existing discussion, so I'd like a clarification:
Is OTW going out and seeking archives to import and then contacting the owner? Are you actively looking to do this?
Or is OTW providing a service to archive owners looking to back up their archives, and only responding to requests coming in from those owners?
If the former, then we have a problem. There are plenty of issues with the archive for the people who have chosen to use it that should be addressed first, rather than spending time on this. This isn't OTW's mission, to scour the internet for content to scoop up.
If the latter, then anyone objecting to "piracy" needs to talk to the people who run the archives they have fic on, and if that owner is considering this and you don't want it, take your content down. Once you posted to an archive, you put your content in that person's hands. You need to take this issue up with them.