Legally perhaps, but morally, I've never gotten why so many people think that the physical act of pulling or not pulling makes so much difference.
It's a binary decision with two outcomes, in my personal view it is irrelevant which of the outcomes is caused by physical action and which by inaction (at least, supposing that you have enough time to think about what to do - obviously, if you have to react in a split second, it's understandable to be biased towards inaction because you may need more time to make the right decision, but that's not the point of these problems in the way they are posed).
If you have enough time to think what to do, inaction is a conscious choice and if it does more harm than good, you are guilty of not choosing action.
It's a binary decision with two outcomes, in my personal view it is irrelevant which of the outcomes is caused by physical action and which by inaction (at least, supposing that you have enough time to think about what to do - obviously, if you have to react in a split second, it's understandable to be biased towards inaction because you may need more time to make the right decision, but that's not the point of these problems in the way they are posed).
If you have enough time to think what to do, inaction is a conscious choice and if it does more harm than good, you are guilty of not choosing action.