My half-baked theory (or maybe not) is that it was called Cardassians because of the way O'Brien would refer to them, and Rugal in particular.
I absolutely love the episode though - it's the strongest of the season so far for me. The presence of Garak helps, and his role is far more memorable than from way back in Past Prologue. I also love that it's O'Brien that has to live with Rugal, as his hatred for the Cardies was established way back on TNG. It was good to see him overcoming his prejudices and realising that he has more in common with them than he realised.
This is Dukat's first episode since the pilot, so the episode is well blessed with good character. It's so much better than the silliness of the last episode.