I think you can love a job without taking it too far. It's true that someone who loves a job could be taken advantage of by an employer who feels like that gives them leverage. And it could lead to problems with work / life balance.

But, I don't think that means a middle road is impossible. One can love food without being overweight. You just have to practice moderation. Loving something doesn't mean there are no limits to how much of it you try to cram into your life.