That said, as OP was saying the overwhelming take (from what I’ve seen) in the gun/conceal carry community has a pretty high standard for deadly force. In reality the standard for “fear for your life” is actually really high for most people. As you say “shooting back” - which implies you were shot at first. I think in that case “fear for your life” is very reasonable and push come to shove anyone with a gun would use it.
This take even stretches into robberies like this. If someone comes up to you on the street and demands your camera (even with a weapon) it’s best just to cooperate and hand it over. All but the most fervent gun people at their core realize that real life isn’t Hollywood. The vast majority of people who say otherwise are keyboard warriors/wanna be tough guys that have never been in such a situation and have some delusional fantasy of themselves channeling John Wick when/if it happens to them. Obviously that’s not reality.
Clearly the US has a ton of guns and there are many millions of people who are armed at all times. Stories in the news of people using a gun to defend themselves are few and far between because 1) violent crime is actually exceedingly rare statistically and 2) even most gun people realize it’s not OK to kill someone over a camera/wallet/etc even though you may have the means to and the law is technically on your side.
Without a concealed carry permit, any law-abiding citizen who travels with firearms in California must keep them unloaded and in a locked container [0].
It used to be incredibly difficult (nearly impossible [1]) for regular citizens to obtain a concealed carry permit in San Francisco because they had a "Good Cause Requirement" which essentially meant that your cause was not good enough.
Apparently, that changed in June of 2022 with a recent Supreme Court Ruling [2].
There are also [3] many stories of victims who shoot their attackers either being prosecuted criminally or sued for civil damages.
Lastly, while the views on concealed carry vary widely throughout the US, most social environments that I ever encountered in Northern California would find it repugnant.
[0] https://oag.ca.gov/firearms/travel
[1] https://www.desertsun.com/story/news/nation/california/2022/...
[2] https://www.sanfranciscopolice.org/get-service/carrying-conc...
[3] Oregon, not CA https://www.gilmanbedigian.com/man-who-shot-intruder-in-his-...
Depends on the particular laws of where you are. The reality is that even if the laws favor shooting back, if the criminal ends up injured or killed it means years of legal issues for the shooter. This is true for any physical altercation regardless of if weapons are used.
Stand your ground laws exist but even then the training literature is quite clear - you run the risk of ruining your life at least financially by pulling the trigger so you better have that as the better option compared to death or serious bodily harm.