A Canadian born person can Identify as an American, the same way a Nigerian can Identify as Japanese.
The world is ours to share, and genetics, DNA, lineage mean nothing. I live close to America, closest than most who aren't currently living there. Think of all the European posters, Asian posters etc. I can travel to America within 3 hours. I know friends from America, and family that are citizens there. The number one thing people will tell you down there is, 'If you feel like you are American, you're an American'