Oh it's not an accusation : the US is the least loyal, least reliable ally you could ever have. Every single occasion they've had to demonstrate it, they did. They'll get you in deep shit, use you then leave you.
Welcome to living among humans, where choices are made.
Every country made their choice, willingly or not, then lived by it for several generations. Now we have a generation of nationalists, we'll see how that ends up down the road for better or worse.