I will say this though: having lived in both Beijing and London, I've always felt ultra safe (and I lived in London during some terrorist attacks). On the other hand, I lived in SF for the same time and I never felt safe there, avoiding walks at night, avoiding public transport for the most part, avoiding some streets, etc. I also lived in Chicago and I felt much worse there (at least in SF I could still take walks).
Also having lived in London for 7 years, I can't say I felt safe walking at night other than in the very central places. Try visiting Elephant and Castle or Seven Sisters alone during the night.
Edit: spelling
Did you ever park outside a parking garage?
Did that many times, it was fine? Only place I've ever felt unsafe was Brentford after I got hassled there.
That's fined pretty swiftly.
Would Chi or SF become a London or Beijing with CCTV?
Doubtful to both. But a lot can be explained by social determinants of wealth and what that turns people into.
Depends where you are and what times.
3am on the redline in the northside.. Be ready to move at a moments notice.
After that some homeless people screamed at me, some tried to punch me slowly (easy to avoid), I got used to it with time but it's still not a nice feeling to take walks. I wouldn't let my SO walk alone at 3AM through the streets for example (while I would have no problems with that in London or Beijing).
Murder rate in San Francisco: 5.17 per 100,000.
Spend some time in a real autocracy, then see if you feel the same way.