Heat the oil in a large skillet over medium-high heat. Season the ribs with salt and pepper and sear on all sides until well browned. The beef ribs should register 70˚C (158˚F) on an instant-read thermometer; set aside.
Discard the excess fat in skillet. Reduce heat to medium, sauté the onions, carrots, celery, green pepper and garlic until lightly browned, about 5 min.
Transfer mixture to slow cooker. Mix in the ribs (and juices), tomato, kidney beans, black beans, tomato paste, chili powder, oregano and hot sauce. Cover and cook on LOW setting for 6 hr. (or 4 hr. on HIGH setting). The chili should register 74˚C (165˚F) on an instant-read thermometer. Just before serving, stir in chopped cilantro and parsley. Serve with bread on the side, if desired.