Been too long since I saw the episode. Skimming the transcript, this is the quote I remembered:

It never occurred to me. This is what I am. Did you ever tell me that you are only a single being? Of course not. That was normal to you.

And since Beverly gives no real pushback to that, I kind of assumed that was a fair justification: that the Trill as they existed in this episode simply hasn’t had enough contact with other humanoids to know they were different.

But skimming the rest of the transcript, you're right. Odan doesn’t correct anyone who refers to his previous work as that of his father. He clearly understands this difference and purposefully hides it.

Feel like that makes the episode less interesting. And especially worse retrospectively if we apply the obvious trans metaphor...

they weren't aware their current one would expire in her lifetime or that they could be saved if it did.

or that they'd be accepted as a symbiotic lifeform if they were found out