Season evenly with salt, pepper, garlic powder, paprika, and oregano. Rub in on all sides.
Pour half the BBQ sauce over the ribs and brush to evenly coat all sides.
Transfer the ribs to a large slow cooker. Position the ribs so they are standing up, with the meatier side down, and so the meat side is against the walls of the slow cooker, with the bone sides facing in.
Cover and cook on low for 7 - 8 hours, or high for 4 hours. Check after the allotted time, you want to make sure the meat is cooked through and tender, but you do not want it to be so tender it falls off the bone. If they seem a little tough, allow to cook an additional 30 minutes, as needed.
Remove the ribs and transfer to wire rack set over a foil-lined baking sheet.
Paint the ribs with additional BBQ sauce, ensuring they are well-coated on both sides.
Broil HIGH for 5-8 minutes to caramelize the sauce, making it slightly charred and bubbly.
Remove and carefully cut between the bones to separate into individual ribs.