Earlier quoted context omitted.
It does feel like somebody forgot that "from the first sentence or two of the email, you can tell what it's about" was already a rule of good writing...
You sometimes need to want to quickly learn what's in an email that was written by someone less helpful. Eg sometimes the writer is outright antagonistic, because they have some obligation to tell you something, but don't actually want you to know.
Those kinds of emails are so uncommon they’re absolutely not worth wasting this level of effort on. And if you’re in a sorry enough situation where that’s not the case, what you really need is the outside context the model doesn’t know. The model doesn’t know your office politics.