Until proven otherwise, I'll assume it's incompetence. I mean, I can't imagine why the Attorney General's office would want to do it. What would they stand to gain? There's no question who is responsible for it, and very little question that they'll be punished for doing it. What would the hoped-for benefit be?
The Supreme Court recently forced California and 9 other states to loosen up CCW rules and there's probably going to be a large increase in applications. Doxxing people with CCWs will have a chilling effect and prevent at least some people from going through the process.
Edit: something else I just thought of. Gun-owning judges are explicitly called out in the spreadsheet. Gun-owning judges are also probably less likely to agree with Attorney General Bonta when he's in court. Is it possible that those judges will have to recuse themselves in cases involving Bonta?