Here for rides.
The instruction needs to be understood in context, it was an attempt to clarify what the punishment should be, not what the definition of a dangerous tackle was, so that a particular type of dangerous tackle would be reffed consistently at all levels of the game because people were asking 'in game A player X got a YC but in game B player Z did near identical things and got sent off.'But that isn't what the instruction says - so we're back to interpretation. I'm not saying that the ref was necessarily wrong, just that it was a matter of judgement.
A ref who consistently misjudges what constitutes a dangerous tackles, something I've been guilty of myself to some degree in youth rugby, or misjudges other sorts of dangerous play, is a ref who will have a short career.