From internal emails within the Mega group, regarding rewards paid under their "Upload Rewards" program:

   100 USD [USERNAME DELETED] 10+ Full popular DVD rips (split files), a few small porn movies, some software with keygenerators (warez)
   ...
   100 USD [USERNAME DELETED] Popular DVD rips
   100 USD [USERNAME DELETED] Some older DVD rips + unknown (Italian series?) rar files
   ...

Again, under the DMCA, it is not enough to simply respond to takedown notices. To qualify for safe harbor immunity to copyright liability, you have to not be aware of any infringement on your site, and if you become aware of it, you must expediently remove that content from your site.

These clowns became aware of copyright infringement and then paid people for it. They're fucked. I have no idea why you think this linking issue matters.

You should read the indictment.