It's not a citywide problem - just a few neigborhoods - but the chance to make downtown businesses kick in more money to the City's general fund to combat this "scourge" (to "stick it to The Man", in other words) is too good to miss.
You are correct.
The main pockets of gangdumb are, I think, mainly: Hunter's Point/Bayview and only pockets there, parts of Chinatown (probably near Ping Yuen, the housing project), the Tenderloin (always has been a sludge area, even in the 40's when my parents were around) and the Mission District (16th & Mission and 24th & Mission).
The "stick it to The Man" attitude is always present, compliments of the non-profits, ACLU and the plethora of advocacy groups that start, grow, thrive, get rich and generally run on that very premise.
Woe betide "The Man" who doesn't bend over for said same groups.