Thank you, everyone.
Let me specifically address the responses about shooting the guy.
1- I saw him for three seconds. I thought it was my wife heading to work and I was going to give her a kiss goodbye. So I was kind of surprised that it was a thief. If I were going to shoot him that would mean that I was going out to say goodbye to my wife (who I initially thought was the person in the living room) with my gun loaded, armed, and pointed at her. So that's not a recipe for a healthy marriage. Being in a position to shoot the guy would also have meant being the kind of person who carries a loaded gun around my own house with me all the time. I have no interest in being that kind of person.
2- The Bay Area does not frown upon shooting home invaders. This state's gun laws are incredibly lax compared to where I used to live (Illinois) and to where I am moving in a few weeks (Colorado). In fact, one of the responding officers looked at me and said something to the effect of 'if this guy comes back, California law is VERY lenient with whatever you feel you need to do to protect your home. You can't do anything to him outside, but if he's inside, or ends up back inside, you're free to defend your property however you want.' I bought my first gun in Illinois and I had to go through two full days of safety training before I could buy it and then also complete tri-annual paperwork and updates with the Illinois State Police confirming that I still owned it. Here, I'm required to ever take zero training and didn't even have to register my gun with the state.
3- I've been robbed before, at a job where I worked retail. The kid then had a balaclava on, so I didn't recognize him, and I did have the opportunity to stop him using lethal force had I chosen (that would have meant a lot of risk to me, too, but let's assume that I could have killed him.) The kid who robbed us was the son of one of the police officers who frequented the store and I would have killed the child (who was my age) of someone I knew. So that would have stayed with me my whole life.
I have known people who have killed people and I have seen what that does to them, and the mental difficulties and challenges it brings, repeated nightmares, and, in some, a vacancy behind their eyes that develops over years of worrying about what the act of killing someone does to them and means for them.
It's, frankly, disgusting that Americans are so flippant about ending a person's life. The most common reactions I've had to this event is people saying things like "That would have ended differently for that guy at my house" or "you should have murdered him then had breakfast" or "Why not just shoot him?" All those are exactly word-for-word. Why not kill someone because they have $1K in my camera gear in their arms? Because every human life is worth infinitely more than $1K in easily replaced camera gear. Every person is worthy of redemption, forgiveness, and kindness, no matter the circumstance. Because a camera thief is human, and has in them all the qualities associated with humanity. People don't break into homes and take a paltry little sum of camera gear because it's a hobby. They do it for a need, and whether that need is rent or drugs, that person is in a bad place in their life. I don't need to make it worse. And anyone who writes off a person so easily needs to question their own humanity. I'd much rather be surrounded by camera thieves than people who think it's okay to kill someone because that person is stealing something I can go online and replace tomorrow. All people are worth more than any material item.