That's correct. A good percentage of paralysis in American Football happens because of, not in spite of, helmets. As you pointed out, some players lead with their heads, which puts extreme pressure on the neck. Helmet to helmet contact is now illegal and players are taught to tackle with their face up, but it still happens. In rugby, they teach you how to go down and go into tackle correctly.
thankyou. it seemed that no one was taking notice of this point. helmets are like airbags in cars. they do maore damage than good