If everything else in the movie is fine, that individual plot point would only be a bit problematic with that character being the only woman and serving only to help Joker's arc. I suspect that the script has way more problems than that, though, and that plot point is symptomatic of some larger issues. That plot point alone wouldn't be worth causing some drama over.I mean I don't know what people expected from a Joker movie, I would expect exactly what that spoiler is.
It's completely dependent on how the movie frames it (i.e. Incel the movie)