Caprica didn't mean to make Bellatrix so angry. She was just doing the thing that she was taught to do by god when she slept with people. She brought them closer to him and she saw nothing wrong with that. It was probably wise to pick Caprica up herself though. Caprica was in rare form lately.
She dressed up in a slinky red dress that would match what Caprica told Bellatrix to wear which was hopefully slinky and black. She liked to match when she went out on dates. It was a thing.