I used to live at 8th/Mission, I have felt the difference you speak of and still I could never live there again. There is a cold, passive hostility there that you don't feel in other places.
That was also the last great opportunity to buy a home there too.
A "safe" SF only existed for about 20 years total.
"Forget it Jake, it's Chinatown"
The recent increase in violent crime in SF is still lower than any period in the 00s or 10s except the three-year window from 2009-2011.