Simple: if it's magic, you don't have to do the hard work of understanding how it works in order to use it. Just use the right incantation and you're done. Sounds great as long as you don't think about the fact that not understanding how it works is actually a bug, not a feature.
That's such a wrong way of thinking. There is simply a limit on how much a single person can know and understand. You have to specialize otherwise you won't make any progress. Not having to understand how everything works is a feature, not a bug.
You not having to know the chemical structure of gasoline in order to drive to work in the morning is a good thing.
I've never found this to be a particular problem. Most ORMs are actually quite predictable. I've seen how my ORM constructs constructs queries for my database and it's pretty ugly but also it's actually also totally good. I've never really gained any insight that way.
But the sheer amount of time effort I've saved by using an ORM to basically do the same boring load/save pattern over and over is immeasurable. I can even imagine going back and doing that manually -- what a waste of time, effort, and experience that would be.
It's about layers of abstraction, the need to understand them, modify them, know what is leaking etc.
I think people sometimes substitute magic when they mean "I suddenly need to learn a lower layer I assumed was much less complex ". I don't think anyone is calling the linux kernal magic. Everyone assumes it's complex.
Another use of "magic" is when you find yourself debugging a lower layer because the abstraction breaks in some way. If it's highly abstracted and the inner loop gives you few starting points ( while (???) pickupWorkFromAnyWhere() )). It can feel kafkaesque.
I sleep just fine not knowing how much software I use exactly works. It's the layers closest to application code that I wish were more friendly to the casual debugger.
It seems common with regard to dependency injection frameworks. Do you need them for your code to be testable? No, even if it helps. Do you need them for your code to be modular? You don't, and do you really need modularity in your project? Reusability? Loose coupling?