Continuity mistake: At the end of the episode, Odo has sent everyone affected by the telepathic matrix to a cargo bay. Sisko and O'Brien remove their com badges, throwing them aside before heading to the bay. After everyone is cured, Sisko straightens back up and, in the closeup, you can see that he has a badge on. In the next closeup, it's gone again.
Continuity mistake: When Kira is explaining to Jadzia in Quark's that she wants to get rid of Sisko, she is wearing her Bajoran earring in her right ear. When she picks Quark up by his collar a couple of shots later, the earring is gone.
Answer: Part of the answer is found in "The Search: Part II" (season 3 episode 2). The female changeling told Odo that "the urge to return home was implanted in your genetic makeup. So he hardly has a choice in that. But being a sentient, thinking being, he recognizes the atrocities that his people are behind and he can't condone their actions. So it's a matter of his conscious mind warring with his instinctual gestalt. But on a more general level, we all instinctually wish to be among people who are like us. No matter how much he may like and love those around him and feel that emotion returned, there are numerous aspects of his life and existence that absolutely nobody on DS9 can empathize with or understand. And that's not even to address the pure joy and acceptance that is brought by the Great Link.
Garlonuss ★