That sign isn't actually referring to 19th and Hackensack Plank, rather warning about Pleasant Ave being closed between 32nd and Marginal. I believe the reason they get away with that is they have police actively forbidding anyone trying to use it as a throughway. Anyone specifically accessing the block of Pleasant (and for that matter, 33rd) is allowed to pass. It's done to alleviate the intersection at 31st, which 9/10ths of the time is being manned by police as well. Other approaches in town are still allowed, and it's not a blanket that all out of towners can't use the road, even if you live in town you can't do it. That's the distinction.