I edited in that I didn't mean for that to come off as aggressive. I'm sorry for that. 
That's fine. No harm, no foul. Let's start over.
Well, that's not entirely true. Zarathian asks the Warden to cure the curse before helping with the Blight, hoping the Warden will handle his problem for him, thus 'serving their own interests'.
In exchange for the clan participating against the Fifth Blight. It's a two way street where some of the Dalish are certain to die, and it's due to a treaty that the Dalish signed with the Wardens to aid against the Blight.
There's also a clear change in demeanor from some of the clan when The Warden shows that he can be trusted, like when Sarel positively remarks on The Warden helping Elora with the halla, who are sacred animals in the eyes of the Dalish. Sarel is off-putting for a lot of players because of his negative attitude towards the protagonist, but he's also mourning a wife he recently lost to the werewolves.
You mean the Velanna they exiled so didn't want her around anymore? When you want someone to take something you don't want, you act nice about it. Otherwise they pose questions and may not get rid of your burden for you.
Actually, Velanna receives a fairly frosty reception from her clan, and The Warden can actually intervene in the conversation and say that Velanna has changed.
I'm not trying to vilify the Dalish. I asked out of genuine curiosity, nothing more and nothing less.
Honestly, they're just different. The clans can vary greatly from one another, and even those among the clan aren't the same. You also need to take in perspective that the clans generally aren't welcome in human lands, they typically get chased out if they stay too long in one place, their religion was criminalized, and they can get pursued by templars because of the elven mages among them. It's not really a lifestyle that's conducive for trust.
There's good and bad among the Dalish, but I wouldn't take the view that the bad is all there is.