Even negligible amounts of something that never goes away and builds up in your blood is a problem.
On top of that, how much PFOA would you imagine is even in a frying pan? It's already so little it's considered negligible, so unless you are buying new ones every day, even the negligible amount is not "building up".
No it's not. You misunderstood what you read.
To kill birds you have to burn the Teflon, and the Teflon smoke kills them. And you have the get the pan HOT - way hotter than anyone cooks. Teflon is not easy to burn, you can put a blowtorch on it for a short time and not affect it.