CHICAGO — The city of Chicago has framed its school speed camera program as a way to keep kids safe, pushing back against claims it’s a cash grab by pointing to a simple rule: Drivers don’t get tickets on days students aren’t in class. One day last fall, that standard broke down. On a Friday in November when a Southwest Side charter school was closed to give students a chance to get vaccinated against COVID-19, nearly two dozen cars nonetheless got hit for speeding in the nearby automated camera “school safety zone.” Eight of those drivers near Acero’s Major Hector P. Garcia M.D. High School g…