He's not using the word correctly, in my opinion. It's a fancy-sounding word, maybe he liked that about it. :) He's saying that he used to love his job. You may be able to get into the "nitty-gritty" or the "details" or the "whys and wherefores" of why he used to love his job and why he doesn't love it any more. But you could only get into the "logistics" of why-he-used-to-and-no-longer-loves-his job if the reason involved a military operation, or some kind of supply-chain involving ordering, storage, and delivery. And that seems unlikely.
Maybe he meant "the logic" or "the rationale for". Or, maybe he actually is talking about "the logistics of <some enterprise>" and not "the logistics of my-once-having-loved-my-job" but if that's the case then I'd urge him to say "the logistics of <some commercial or military operation or other>".