I think with people mean is “real bugs.” The bugs the game has are very expected and, by all accounts, not game breaking. Meanwhile AAA studios drop content at launch, charge for everything after you’ve bought it, and have game breaking bugs that force you to restart regularly or sometimes ruin your games. I mean come on, look what happened with. Halo: Infinite and Redfall. It wasn’t goofy animations and such.
No game is truly “bug free.” It’s a catchall term to say “I can play this game from start to finish without any particularly memorable issues.”