By Brendan O’Brien (Reuters) – Relatives of children killed in the Uvalde school shooting confronted the Texas public safety director on Thursday and demanded he resign over the failure of his agency’s troopers to confront the gunman quickly and possibly save lives. Brett Cross, uncle of 10-year-old Uziyah Garcia – one of the 19 children and two teachers killed in the May 24 shooting at Robb Elementary School – was one of several relatives who pressed Director Col. Steven McCraw to follow through on his vow to resign if his agency was found culpable in its response. “You have disgraced our sta…