First of all, posting upscaled videos is contributing, as long as it is enhanced as well, and not just changing the resolution but keeping the crappy quality
Lots of people repost content all the time in the form of *Blacklisted site* or mega links they found. They post it in the thread without bothering to check if it's been posted before. We get reports about it every single day from people and have to delete posts to cut down on repost spam every day.. You may not like it, but it's a rule and it's not changing.
Think about the amount of people thst will be getting notified of a new post, checking said post, and realising it's basically the same content they've already seen but altered using third-party software.