I watched that one last night and had the same thought - she's been the face of nonacceptance towards Data and although Bruce Maddox is far more extreme in his views it seemed like a waste of her character building.
That said, they'd already shoehorned in a Guinan scene so I don't know where they'd find the time.
Picard's scene with Guinan was not in the original script. Melinda M. Snodgrass was told that they needed a "Ten-Forward" scene to accommodate Whoopi Goldberg coming in that week.
I took it as true, although I had a quick go at finding where this claim came from and am drawing a blank
I think obvious that she would have sided with Maddox and disagreed with the ruling. I don't think her capable of overcoming her prejudices against artificial life forms.
I think that's something that gets forgotten. Season 2 gets skipped through a lot during rewatches I know. All anyone remembers is her being racist to data.
She starts out mean to Data but she comes around by the end of the season. She is also a former lover of Kyle Riker, which could have made for a much more interesting dynamic for and with Riker if it had continued.