I double checked what Nal said myself by browsing through a couple of WWS logs from Horde guilds that use Ret Paladins (Blood Legion and Celebrity are two), and none of those have any Judgement of Blood resists in there either. I only browsed through about 200 Judgements worth though, and there's obviously the chance it's based on melee hit, but I assume it's correct for now since the original report came from a Prot Paladin.
Also double checked to make sure it isn't the same bug as Holy Shield and Greater Blessing of Sanctuary have (Both of those show as "<player> resists <mob>'s <ability>" despite being used by you), so it seems Judgement of Blood is indeed incapable of resisting in PvE situations.