A dominant religion doesn't necessarily have to assimilate others. The Romans, for example, didn't care what their conquered subjects believed, as long as they paid their taxes. It was only in the late empire that religious persecutions took place, generally against Christians. Conversely, a minority religion can certainly have a proselytizing mindset -- you might say that's how they go from being a minority to a majority faith in the first place.
Yeah, you're right, I didn't mean to say it as a blanket statement. Genghis Khan is a great example of this too, he actively encouraged the spread of ideas and dialogue between faiths.
Andrastrianism however becomes a justification of those colonizing actions, because turning people "back to the Maker" is a mandate of the faith, so converting as many people as possible means opening up the faith, I think.
Anyway, I think its strange to take "sides" when it comes to Sera vs Dalish Quizzie. Neither is wrong or right, they are just coming at something from a fundamentally different perspective. The biggest problem, as others have noted, is that the scene doesn't allow Quizzie to react as naturally as Sera does. This is a consistent problem in the game, I think, where the PC's dialogue is mostly reactive to the needs of the characterization of the NPC, instead of a balance between two individuals.
Another, less controversial, example of this is when you first meet Sera and she explains her "friends" to you. You're given the option of asking her if she is offering spies, soldiers, or noble allies. This dialogue is set up for Sera to correct you, and doesn't allow for the perspective that a PC might automatically understand what she's offering. Which for my Carta dwarf, felt very off. But the scene is very effective for Sera's character. It's a difficult balance, offering a fully voiced protagonist who is customizable but limited by word budgets, and I think that this game had a lot of issues with it. Hopefully something they'll learn from moving forward. Sera is hardly the only character who suffers from that, Solas is another big one, IMO.