Hooks are functions, and they are executed in the order called from within the component, which is itself a function, just like any other functions calls from within another function.

(The mechanism tracking calls to them and deciding whether the function passed to the hook needs to be called requires them to be called in the same order each time the component is executed; if they were called in order of definition rather than normal execution order this would be true by definition; the whole reason for the rule about not using flow control around them is that they are functions executed in normal flow order.)