

One of the issues the Trolley Problem explores is people’s differing willingness to allow harm versus cause it. And that can hold even when the level of harm caused by inaction is significantly higher than what is caused by taking action. E.g. If your personal philosophy dictates that killing someone is always wrong, does it hold if your inaction causes 5 deaths, 10, 50? What if we start tinkering with the people dying? Would you kill a 90 year old man to save a train full of children? The Trolley Problem is really just a starting point to examine that dichotomy between causing harm and allowing harm and just how permeable the line between them can be when you start changing the conditions. Attaching other moral choices to the problem is one way to use the problem to explore a set of beliefs.
Yes, exactly. By taking no action some amount of harm occurs, had you taken action that harm would not have occurred but other harm would have. Ultimately, this is analyzing the extent to which a person is willing to allow harm via inaction versus cause harm through direct action.
Like many thought experiments, the Trolley Problem is an artificial situation intended to isolate certain decision making points so that they can be analyzed. Yes, reality is messy and we often have more than two options. But having this sort of analysis ahead of time can make the real problems less complex to consider. It is also useful for looking at our philosophical frameworks and where they break down.
The Trolley Problem is a tool for examining our beliefs. Throwing it away because it is imperfect and uncomfortable only leads to a blindness of self.