What has malice got to do with it?

Western Province move the ball to their right and Francois Louw drives forward. Ashley Johnson grabs low, his left arm firmly around Louw's throat which forces Louw's head back.

This situation continues for some 12 metres as Louw grabs across the field with Johnson's arm around his neck.

Western Province win the ball and it goes left where Paul Bosch of Western Province knocks on.

The referee stops play for the knock-on and takes time out to go to Johnson and tell him that what he had done was not malicious and he should keep his tackles down. He then goes off to the place of the knock-on and awards a scrum to Free State.

It is not good refereeing.

The law deals with facts not malice aforethought or any other form of mind-reading.

Law 10.4 (e) Dangerous tackling. A player must not tackle (or try to tackle) an opponent above the line of the shoulders even if the tackle starts below the line of the shoulders. A tackle around the opponent’s neck or head is dangerous play.
Sanction: Penalty kick

Did Johnson tackle Louw above the line of the shoulders?

Yes.

That is, according to the law, a dangerous tackle.

The sanction for such a tackle - even attempting such a tackle - is a penalty - at least a penalty.

One can understand Johnson's relief.

It was also a case for the assistant to flag.