true that shield slam mitigates from armor but our ShoR does not. even if i hit a naked person it does the same damage as it's holy damage.
if you don't like that video then here's more:
http://www.youtube.com/watch?v=6CzOMRmErrg (mainly the end part, with same block value as me they get 13k+ and we only get ~10k, usually less)
http://www.youtube.com/watch?v=y3wcNcavPnk
http://www.youtube.com/watch?v=VVPFQNV97sg (lame but you get the idea)
not many people post Prot Warrior pvp videos though. just like Prot pally pvp is basically just me and Chronalis.