I'll admit the songs themselves are most likely copyright infringements (For the "official" bumper packs and probably 80+% of the "originals"). But the steps themselves are hand recreated (and refined roughly every month). I do know that the main website that creates and hosts these, DDRUK.com has had them up for a long time and as far as I know has not been served with a C&D letter or any other form of legal threatening, and the site is one of the more popular DDR sites out there.
If you decide it's too iffy and remove it, I'll make sure to never post it again.