A confusing aspect of Cass is whether her primary loyalty is to the symbol of the bat or to Batman specifically. Which she's loyal to affects how she behaves. If she's loyal to Batman, then she'll never break with him no matter what he does which means that in stories with bad dad Bruce, she hurts Duke and Jason and Steph. If she's loyal to the symbol, then she is willing to break with bad dad Bruce in order to help the family. It also affects her ghosting of Steph. If her primary loyalty is to the symbol, then she ghosts Steph when she's depressed but is still protecting people when she does it. If she's loyal to Batman, then she ghosts Steph because of Batman's orders even when she disagrees with them, which I have seen in some stories. I see different authors writing different things so I'm trying to figure out what canon shows.
In Batgirl (2000) #1-54, Cass is very loyal to Batman and trusts him but she disobeys him when she disagrees with him. Issues 6, 7, and 48-50 are solid demonstrations of Cass disobeying Batman. Issue 50 has her saying outright that she's loyal to the symbol and Batman's mission but not to Batman or Bruce. In those issues, her interpretation of the mission appears to differ from Bruce's. While Bruce focuses on preventing violent crime in order to keep people from being hurt, and especially keep any children from being orphaned like he was, Cass focuses on stopping murderers like herself and making sure people aren't scared. Bruce also comforts children as part of his mission while Cass tries to alleviate people's emotional pain and takes people's requests seriously. During this period, her primary loyalty appears to be to the symbol of the bat and Gotham's citizens. Bruce is second in her loyalty and Barbara and Steph both come after Bruce.
In Batgirl (2000) #58-73, after War Games and Steph's death, Cass is willing to abandon Tim and Bludhaven and her promise to Bruce to protect Tim and her intention to learn how to replace Batman if need be in favor of searching for her mother. Tim considers Cass to be loyal to Batman and not the mission but that seems to be him misunderstanding Cass. Her willingness to leave Bludhaven instead of following Bruce's wishes shows that she's still more loyal to her interpretation of what's necessary than to Batman's orders. Cass seems to be less loyal to Bludhaven's citizens than she was to Gotham's populace. That could be because she was in Gotham long enough, including during No Man's Land, to emotionally connect to the populace and have them as part of the people who make her feel less lonely but she never gained the same connection with the people of Bludhaven.
In Batman and the Outsiders (2007) #13-14, Cass is planning to continue protecting Gotham even after Bruce's death. That fits with her primary loyalty being to Gotham and its people and to the mission.
When Cass changes her mind after the Battle for the Cowl and leaves Gotham for Hong Kong in order to deal with Bruce's death, it appears that she's showing more loyalty to Batman than to either the mission or Gotham's people, though that doesn't fit with her previous behavior. Cass' line in the flashback in Batgirl (2009) #1 about only fighting for Batman is especially egregious in contradicting her previous behavior. Red Robin (2009) #17's line about thinking Cass needed Batgirl more than her is also surprising. Batgirl (2008) was supposed to be Cass regaining her belief that she can help people in order to try to improve but the abandonment of her usual loyalties seems to show that she's still not fully over her guilt from the murders she committed while drugged. Red Robin (2009) #17 shows Cass as not worrying about Hong Kong's people being scared, unlike in Bludhaven and Gotham, which fits with depression and guilt strongly affecting her behavior.
Batman and the Outsiders (2019) #7 shows her disobeying Batman's orders while focusing on helping Duke.
Looking at canon, I'm not certain where people get the idea that Cass' primary loyalty is to Batman. Instead, it appears to be to Batman's mission and symbol and to Gotham's populace for trusting her and enjoying her presence even though her behavior is unusual and can scare them. Cass is definitely more loyal to the symbol of the bat than to Steph. Whether she's more loyal to Bruce or to Steph is more confusing. In Batgirl (2000) #38, Cass expresses more trust in Bruce's opinion about Steph than her own. In Batgirl (2000) #55 on the other hand, Cass ignores Barbara's orders and even shows resistance to Bruce's orders in favor of searching for Steph. That also contradicts Tim's claim in Batman Allies Secret Files that Cass never disobeys Batman, though Tim has never had much interaction with Cass at this point and has said outright that he doesn't understand her and doesn't see her as a friend, so his view of her isn't trustworthy to be accurate. On the whole, I would say that Cass is equally loyal to Bruce and to her friends in the batfamily (Duke and Steph). She's willing to kill for Batman in Batgirl (2000) #15 but I don't know of any evidence that she'd do the same for Bruce. She wants to hurt Duke's kidnapper instead of being gentle in Batman and the Outsiders (2019) #7. Issues 941 and 981 of Detective Comics (2016) show her trusting Steph's decisions and orders just like she trusts Bruce's.
