This can only go so far. What about players on Offense who lower their helmet to gain that extra couple yards, causing the defense to go helmet to helmet? There has to be a leniency or slack with this rule. There are accidents. They shouldn't eject for that.
Lowering your helmet is not launching yourself into a player. That's not the issue here. If you come full speed, leave your feet, and then make helmet to helmet contact, that will be grounds for ejection.