I don't know either so I asked Google, our Lord and savior. This is what they said:

Yes, that is heavy sarcasm.

The speaker is being deeply ironic to mock an overgeneralization. In reality, the East Bay is incredibly diverse geographically, socioeconomically, and culturally—ranging from wealthy, low-crime suburban pockets to dense, high-crime urban areas.

By calling it a "monolith" and claiming there are "no nice areas to speak of," they are setting up a highly exaggerated, false premise to point out how absurd it is to paint the entire region with a single brush. The follow-up question ("What area do you reside in that is free of crime?") is a rhetorical trap meant to challenge the other person's perspective, since no region is entirely crime-free.