Most of the residents were Bajoran so I don't see why it would be so surprising. Next to all of them would have lived during the occupation, so the danger of DS9 probably pales compared to that. The next biggest group would probably be Starfleet families and they might have a better understanding and acceptance of the risks.
Then there's Quark. Sisko flagged him as the lynch pin. His staying signalled that there was a commercial future on the station, it encouraged others to stay making it more palpable for civilians to want to live on the station.
As for the Vulcan restaurant, Vulcans were probably the most mentioned group in terms of exploring the GQ, so there might have been a healthy flow of Vulcans through the station. Diversity also would be a factor, if there are enough people wanting to eat Klingon cuisine, whick seems to be meat or alive dishes, there probably are people who would favour vegetarian Vulcan cuisine.