Completely justified complaint though, like she was being completely unreasonable and selfish forcing you to deny a part of yourself just to continue the relationship. No compromise, no middle ground, no inch of respect for your Dalish elf's beliefs. Sera has many faults, that was a glaring one IMO.
This goes a bit in to 'personal stuff' territory, but...
Some people collect their troubles in their mind and bottle them up. They don't speak of them and for the most part, they are fine as they forget old worries as fast as new ones come in. And then suddenly there comes a tidal wave and everything starts crumbling. At this point, some will seek help in other people but others will just continue to try and bottle it all up. Sera is the former type. No, her request isn't reasonable or rational. But it doesn't matter to her as she is fighting to keep herself from coming apart. The inquisitor is her liferaft and she is clinging as hard as she can. The look on her face she has if you question her about it is the same that I saw on the face of someone I cared about a great deal who, similarily to Sera, had to suddenly face a tidal wave she was not equipped to handle. Only she was an example of the latter kind of person. And honestly, I'd rather take Seras direct confrontation than 'I'm fine' and 'It's nothing', that look of pain and shame on her face, and watch her withdraw in to herself further and further every day without being able to do anything about it. Once in a lifetime, never again.
...Too much info?