Understanding Hard-Hitting Rules

[Defensewins]

What the rule makers and fine makers fail to realize is it so easy to see a play in slow motion and theorize the tackler could have done this or should have done that. In some cases the game and play is so fast that the defensive player/tackler is lucky just to make contact with a WR that runs at 4.3 speed. Much less does the tackler have the options to decide where he is going to hit the offensive player.
The other point you already talk about is the issue when the offensive player lowers his head at the last second and thus accidentally makes head to head contact with the defensive player. That is not the defensive players fault.