Why should we take the word NATO generals or Western policy experts over the word if the man who is responsible for the lives of the Ukrainians who will be piloting the F-16s he is asking for?

Again, these planes are a finite resource. Once they are gone, they are gone. NATO doesn't just throw very expensive equipment to the wind like Russia. This is not about the lives of the pilots. They have ejection seats. Its about getting the right bang for the buck out of very expensive equipment and not just losing it on the first day. If the US sends a shit ton of F-16's, and they all get lost within a week or due to insufficient operational and strategic training, then it'll become a shit show politically back in the US and the general public might have less of a stomach for continued support.