So you don't agree with the opinion that it's haram?
Definitely not in a North American context. This is part of the norms here.
+2 answers in: “Today's my dad's birthday. I heard from many different sources that celebrating birthdays is haram because
من تشبه بقوم فهو منهم
But I haven't told my my dad that because he's not that religious. I haven't wished him a happy birthday yet and I'm afraid he'll get upset. What should I do?”