It's actually proper tackling. I don't know why it is not taught anymore. Wrap up and hit low rather than launch yourself at your opponent, leading with your head and hope he falls down. Never made sense to me.
I played rugby for 15 years and can tell you the number of serious head injuries in rugby are far fewer than in football. My opinion is that because in rugby you don't have this false sense of invincibility like you might when you have a helmet and pads on. In rugby you know that if you lead with your head you're going to break your neck. Plain and simple.