a couple reasons: in the hood, gas stations are one of the few places people can go to hang out. they don't have nightclubs, restaurants, bars, cafes, bookshops, record stores, nice clothing stores, sporting goods stores, gyms, ice cream parlours, bowling alleys, or anything of the sort. hell, most hoods don't even have walmart. when you're that deep in the ghetto you don't have much and your options are severely limited. you're basically talking about a place where a slurpee from 7-eleven is considered a treat. you'd be shocked at how many dudes in the hood are living off of gas station food. the other reason is gas stations are checkpoints. have a car? you'll need to stop at one. people who show up at gas stations have things to steal. that could be: the car itself, money, phones, clothing, accessories, tools. for the low-lifes of society it's like a buffet where the food comes to you.  every intelligent detroiter knows you never get gas after dark for these reasons. not to mention the large cop presence. police brutality is very common at gas stations as well.
Task Force Z