I have played both sports. My worst concussions came from fooseball, and those hit also tweak the neck. I'd let my son play hockey as a 5 y/o, but am not willing to let him play football until he is 16. To me, the blows to the grape make football perhaps more violent, but surely more dangerous. If I wanted I could easily go on, pointing out how many players leave the football field in a stretcher or paralyzed, the length of pro careers, etc.
I do get what you're saying, but I believe the head shots are a lot more controlled in hockey. Plus, hockey has more of a gentleman's etiquette (you get to fight).