In the BT sport commentary with Care and Dallaglio (neither of whom can exactly be classed as biased towards Saracens), of the three big hit incidents of the match, words from Care/Dallaglio of "that's what we have to stamp out of the game" weren't used to describe the Davies hit, but they were used in the Murimurivalu and Green hits. In the post-match analysis, Care and Dallaglio actually covered the mitigation behind why Davies received a yellow, and why Naulago (in Bath v Bristol) was awarded a red.
The Murimuri hit wasn't to the head, but that doesn't discount that it was a completely aimless high-speed shoulder barge on Lewington who had already scored the try. The camera view from behind is pretty damning to show the force of the impact. The commentary team even state that a yellow was a 'positive' outcome for Leicester, and go onto to highlight the various injuries players have picked up from such acts of late reckless play.
If any incident in the match was deserving of a card/a red, it was the Green neck roll, so it will be interesting to see if he gets cited.