Ward says he went low because going high could draw a fine, and on the surface that reasoning sounds fair.
But here's the thing: Ward (as well as others) acted like there are only two possible areas to hit: the head, and from the knees down. But there's an entire middle section, which includes the shoulders, torso, waist, and upper legs. No fines for that area, and a lot less likelihood of injuries.
And yes, defenders should be trying to wrap up players anyway, not throwing themselves like projectiles, because it's the most fundamentally sound method of tackling.