I don’t agree. If the film is perfectly good, this doesn’t contradict the claim that cancellation has nothing to do with its quality.
Except that's not actually what was claimed. I looked into the various articles, including these:
https://www.hollywoodreporter.com/m...rl-shelved-at-warner-bros-hbo-max-1235191371/
“The decision to not release Batgirl reflects our leadership’s strategic shift as it relates to the DC universe and HBO Max,” said a Warner Bros. spokesperson in a statement. “Leslie Grace is an incredibly talented actor and this decision is not a reflection of her performance. We are incredibly grateful to the filmmakers of Batgirl and Scoob! Holiday Haunt and their respective casts and we hope to collaborate with everyone again in the near future.”
https://collider.com/batgirl-movie-cancelled-warner-bros/
The movie, which cost $90 million dollars to produce, seems to have failed to please the audience in the first test screenings, potentially leading to Warner Bros. Discovery's decision to shelve the project and prevent it from becoming a huge flop. Collider has spoken to people who saw the unfinished movie who told us it was a huge disappointment and looked cheap in comparison to other films.
https://www.rollingstone.com/tv-movies/tv-movie-news/batgirl-shelved-warner-bros-1392407/
Sources say the film began testing with audiences on July 14, and while Grace’s performance was embraced, the overall feedback was harsh. One source familiar with audience testing for the film likened it to “a bad episode of TV,” while another said “it’s definitely not theatrical.”
So I guess I was wrong to think there were two opposing claims, one that said it was about the film's quality and one that said it wasn't. Those are just two incomplete readings of the same thing being reported fairly consistenty: that people liked Grace's performance but were disappointed in the film, and that the disappointments appear to be more about its scale and production values than its quality as a story, so it's not being held against the filmmakers.