I know that the refs have formed a self interest, self help group, but the refs really don't do themselves any favours when mistakes (let's be kind and call it a mistake, as opposed to deliberate) like this happen.
Running through the process. There was contact with the head. I have seen some cheats apologists say it was the chest. No. It was the head. What hit the head? The leading shoulder. Now, that alone is bad posture. Coming from that side, Farrell should have made contact with his left shoulder, not his right.
Did the ball player dip or fall in to the contact? No, or not significantly. Was Farrell upright or bent to make the tackle? Bent, but nowhere near enough. A typical tackle we see week in week out made by a 10. Everything about Farrell's technique was wrong.
Was it at speed, high force, high degree of danger? Yes. Red card. A 4 week ban, reduced to 2 weeks because he has volunteered to help grannies cross the road for a day. The two weeks suspended because he is an awfully nice guy and hasn't made a red card tackle like this in the last 4 weeks. Oh, and nominate him for an OBE because he plays for Sarries at such a low salary, just so they can stay within the cap.
Dickson is what he is. Generally a good ref, bags of experience, who has regular and inexplicable brain farts. He knows it, the RFU know it. His fellow refs know it. The commentators know it. The players know it. We know it. Does that mean he shouldn't ref at this level? Maybe. Certainly demotion to running the line for a season or two. Will that happen? Not a chance.
At this point, do I care? No. The RFU are facing legal action over head injuries. They will claim they are 'doing something'. Lawyers just have to show clips like this to prove they are not doing what they say they are.
I appreciate that you all say the RFU is the only game in town, but they are run by utterly incompetent old farts, and if they were a genuinely commercial enterprise, they would have gone under years ago.