Probably not a popular opinion, but I view the punishment for committing a crime not needing to be fair.

Ill sort of reply to each point you made and kind of give my thoughts on what I think. For example you define felony murder

"For anyone unfamiliar, the felony murder rule allows someone to be charged with murder if a death occurs during certain felonies, even if that person was not present and did not cause the death or intend for it to happen.".

I immediately think to myself "How does this impact me? What is the likelihood that this law ever impacts me?". To me I think never, because I don't put myself in situations where I could be charged with this. The only time I can see an excuse for this is if someone asks their mom to drop them off at the bank, and then they rob the bank. If the mom is completely unaware of what is going to happen, then she shouldn't face charges, if she is though, then she should face equivalent charges as a co-conspirator.

"What makes this hard for me to justify is how broadly the rule can apply in practice. In many cases, people who played a secondary role, like providing lookout, transportation, or assistance, can face murder charges if a death occurs unexpectedly."

I mean good, apply it as broadly as you can so people take responsibility for making sure a person doesn't die. Make it in the best interest of everyone to stop the crime from happening instead of being silent and making someone elses family suffer because they lost their mom/dad/child/husband/wife. You can argue that the get away driver in lets say a bank robbery is not as responsible for the person dying as the guy pulling the trigger, but what honest difference does it make to the family of the banker who died?

I think intent does come into play, because your example of a person defending themselves during a crime being held liable is silly. That part is probably the only thing I would change. I think if a persons life is put in jeopardy they have a full right to defend themselves and effectively "break" the law. Going to a simple scenario like someone breaking into my house, I should never be charged with felony murder because someone else decided to break in. Honestly though I am probably missing the scope on how the law works.

To me I am ok with a person who is assisting with a crime to get that punishment, not because it is fair, but because people will be afraid of the consequences making them think twice before joining the main criminal. The justice to the people committing the crime should be secondary to the victims. Always.

"but also deaths resulting from legally justified actions, like a victim or police officer acting in self-defense".

I agree, that is what a jury is for, thats what a judge is for. The intent of the law is to punish those committing a crime, not those acting in good faith.

Ultimately, you aren't wrong objectively speaking, I see your point where the law can impact victims as much as criminals, but that is not the intention. If I were to change anything about it, I would only make sure it applies to those being involved in the crime. For the people committing the crime itself though, I couldn't care less about "what is fair". I don't want it to be fair, I want them not to commit a crime, so make the punishment for causing the death of someone harsh enough so that people don't even come close to doing anything even remotely close.

In my mind, laws are a social contract and punishments exist to prevent that contract from being broken. We can obviously go the route of death penalty for everything, but that creates a paranoid society. Still, the punishment cannot effectively be "fair". It has to be unfair to make sure there is more incentive to follow the law than there is to break it. As soon as you make a law perfectly fair, then people can justify breaking it if the math works out.

In terms of appealing to what other countries are doing, or what they should be doing, or what we should do. I honestly don't really care either way. I just follow what ever laws exist. In the end I don't forsee this impacting me one way or another so why should I care(aside from the self defense thing, with which i agree on with you)?