The map has MA in blue, representing a duty to rescue, but for most purposes the state isn't. It has a good Samaritan law, but you don't have a duty to rescue a stranger you have no connection to. You would have a duty toward your child, student, employee, invited guest, or similar. As well as if you caused the danger they need rescuing from. http://tramontozzilaw.com/the-good-samaritan-law-in-massachusetts-bystander-protection-and-responsibility/
The map also has CA in blue, but as far as I can tell it only has a limited duty to report and no duty to rescue? https://alexanderlaw.com/articles/2018/02/is-there-a-duty-to-assist-in-an-emergency-situations/
Likewise WA State. It has well-publicized (including mention in first aid classes, and some PSAs) Good Samaritan laws, but the offense for non-aid is only applicable to police officers. There is a "failure to summon aid" that seems to apply to all citizens, but I've NEVER heard about it until now, even with fairly large news stories about exactly this.
Very nearly everyone agrees that there is a meaningful difference between action and inaction?
Alice is trying to decide whether to give Bob $10.
Claire is trying to decide whether to steal $10 from Bob.
If you refuse to acknowledge a difference between action and inaction, you can claim that both of these scenarios represent 'choosing whether $10 should end up in Bob's pocket or in your own', and therefore that these two situations are the same, and therefore that Alice's obligation to give Bob $10 is exactly as strong as Claire's obligation to not steal $10 from him.
Outside of the deep end of Peter-Singer-style altruism, though, I don't think many people believe that.
I think you are missing the point.
Getting back to the example about an old man collapsing in a bank lobby, let's compare three alternative types of actions:
Claiming that there is no meaningful difference between action and inaction would imply that doing nothing to help the old man is equivalent to harming an old man. This is indeed a fairly extreme position, and I agree with you that it is rejected by nearly everyone. In this very real case, the bystanders were fined by the German justice system for not helping, but they were not put in jail, as would have been the case for harming an old man (at least on purpose). So the German justice system agrees with you on this point.
But that's not really the question of duty to rescue. The question is not about the equivalence of doing nothing and harming an old man, it's about the equivalence between helping and doing nothing. In this case, one would be fined for doing nothing, but wouldn't be fined for calling an ambulance.
Without the duty to rescue, one wont be fined, or otherwise punished, for doing nothing. This makes doing nothing a safe choice (at least in term of legal consequences).
Do you have any statistics on impact of such laws (on the rate of intervention, or on the prosecution of bystanders)? I wonder if many of them are wishful thinking or historical preference, and not actively used in modern times. The Good Samaritan versions do have good effects, in making people aware that they won't be punished for trying to help, but the penalties for non-interference seem likely to be toothless.
I wonder if the combination of duty to help and good samaritan laws make "flip the switch" legally acceptable (or mandatory!) for the trolley problem.
If you are waiting in a bank lobby, and an 83-year-old man collapses, do you have a moral duty to try to rescue him, call an ambulance, or provide any kind of assistance? Or, more importantly, do you have any legal duty to do so, i.e. can you be held liable for failing to come to rescue someone when you could have? Apparently, if you live in Germany, the answer is yes. In most of the US, the answer is no.
Duty to rescue
The Non-assistance à personne en danger is (in French) the offense committed when someone doesn't help another person who is in danger. It is an offense in France, Belgium, Quebec (but not the whole of Canada), and, as far as I can tell, most French-speaking countries. In the US, as well as other English-speaking countries, it is known as Duty to rescue, but, besides the non-literal translation, one key difference between the two languages is that it is not an offense at all.
It is actually an offense in only a small number of countries. The wikipedia page provides this very informative map, with duty to rescue in blue, good Samaritan law in cyan, and red, orange and grey being varying levels of no duty to rescue / no data. The good Samaritan law is an interesting concept, where a bystander still has no duty to rescue, but the law provides some protection to anyone who tries to rescue them, if they cause harm by doing so.
The lack of duty to rescue in most countries goes strongly against my intuitions (those intuitions being probably influenced by the law), because it introduces doing nothing as a special and privileged kind of choice. In Europe (at least according to this map), in a situation where someone is in danger, you, as a bystander, should take the action which helps the most (and this may or may not be anything, depending on the situation). In most of the US, apparently, one should either take the action which helps the most, or do nothing. Doing nothing is some kind of get out of jail free card. Actually no, it is a literal get out of jail free card. This introduces some asymmetry between action and inaction, where one is liable for bad actions, but one cannot be liable for inaction. It also incentivises inaction.
On a lighter note, this lack of duty to rescue is the plot of Little Lost Robot, one of the short stories in Isaac Asimov's I, Robot. Without spoiling too much, as we all know, the first law states: "A robot may not injure a human being or, through inaction, allow a human being to come to harm.". In this short story, the second half is removed.
Motivation
I was driven to write this short post when reading Asymmetric Justice, a very interesting post revolving around the fact that one gets punished for bad deeds, but doesn't get rewarded for good deeds. This incentivizes always choosing the option with the least variance, because it is, from this perspective, better to be certain to cause a little harm, than to cause a lot of harm with 50% chance, and a lot of good with 50% chance (since one won't be rewarded for the good anyway).
At least that's how I put it, because the post goes in another direction, and states:
When I read this sentence (which is in the first third of the post, and strongly shapes what follows), I just thought "no, this is wrong". Not wrong in a moral sense (although one could argue it is), but wrong in a factual sense. An asymmetric system isn't against action, it is against variance. In an asymmetric system, one should still take action if this action reduces the expected amount of negative outcome.
That being said, I came to realize that the author probably had the asymmetric system as implemented in the US in mind, where inaction is hard-coded as a neutral action. In this context, yes, since only bad actions are counted, and inaction is always neutral, the system is against action. Note that the good Samaritan law is only an imperfect patch, making the action to help closer to neutral, but never as good or safe as doing nothing. To wrapup, the incentive not to act has to do both with the asymmetric system and the lack of duty to rescue. If you have a duty to rescue, then helpful action is promoted.
It is difficult to draw a satisfactory conclusion from such a post, revolving around moral intuitions and what a legal system should do. I end up wondering if our personal moral intuitions are shaped by the law, and not (or not only) the other way around. I encourage you to go read Asymmetric Justice if you haven't.