It's not described as a definition. It doesn't look like a formal definition. In fact it looks like a summary of the current content which is what it is described as.
And surely the whole point of asking for a definition is to ask for a formal definition. Which that is not.
I don't see why a formal definition would do better than the summary for Coyne's purpose (in fact it would probably be worse). Nor do I think that pointing out the fact that Coyne explicitly says he is summarising the theory rather than offering a definition can be considered "clutching at straws".
Perhaps you should consider why you are so desperate to call Coyne's summary a definition.