JamesDixon
GM Extraordinaire
Because being able to take something down is a fundamental element of online privacy and property rights (who owns what you uploaded regardless). Nexus needn't claim any other right other than the right to keep it up, and that's still a loss for anyone uploading there. Someone always keeping something you uploaded, however sanitized was is still a very bad idea from any kind of rights perspective. The question is why they shouldn't have that right but why they should. And why should they? Because the uploaded material is in a legal grey area? I'd like to see how they respond to their first DMCA takedown notice.
If you want to archive something, archive it yourself. No one is obligated to keep free content up for you. Buy an external HDD, a pendrive or use fucking google drive, which is free up to 15GB. Its still easier than pushing this off the slippery slope into hosting sites wanting to keep your files for millennial economics experiments.
I've already debunked the "property rights" that you conveniently ignored. Copyrights are property rights.