Perhaps it is because of the conclusion, not the movie?

I’ve found there’s a specific type of person who watched it who took offense to the ending. I was one of them.

After years of romcoms I was always told that if you persist you will get the girl. Just be nice to her. She’ll come around.

500 here did a good job shattering that, proving women are not slot machines you have to just keep persisting with. You need to move on. I did not handle that well back then, but looking back I respect the movie