It's still their work. Thankfully, this is not college. A lot of these videos have been in production for months.

That seems like an incredibly conspiratorial answer. The original simply had copyrighted music that would've gotten it disqualified, so he re-uploaded it with acceptable music. It has nothing to do with gaming votes based on past popularity.
Also you could have read all this in the video's description.

A LOT of my freinds are doing this.