Then WHAT(?) constitutes a “Horse-Collar” tackle?

The penalty is when a player gets his hand inside the pads from behind.
I can see where a player can get just as seriously injured when grabbed inside of the pads from ANY direction! The tackle I am referring to gives the ball carrier a means to the end with that grab and that could have been a really bad injury to his neck or head from ANY angle when they are grabbed by anything so solid as their shoulder pads which gives the tackler an enormous advantage of holding on to something so solid as their pads. If it’s worded as you say and it’s only from the back IMHO, there’s a question of where that limit point on the pads is. Is it from the dead middle? Is it from the middle of the shoulder to the middle of the other shoulder? Grabbing a player’s pads seems just as dangerous and just as a way to control the runner or receiver and making the player pretty defenseless to rid themselves of the tackler! Just asking before it happens in A SEASON GAME when it really counts and with our history? Seems as if we’re exposed to any wrinkle or opportunity for a call which either hurts one of our players or costs us a game or player’s health.