I think she is perfectly aware people like the Redcliffe villagers or the mages in the tower aren't trying to trick you into thinking they're weaker they really are, but they are really in situation that overwhelms them. There's difference between deception and actually being weak, and with her experience at deception she's pretty good at telling one from the other.
She's a good character. She's just a pain in the ass to drag through the game, complaining the whole way unless you take the easiest way out.
I understand her siding with wiping out the mages, actually. That one I get.
I don't understand why she gets angry if you stop someone from profiteering, offer to save the Blacksmith's daughter or lots of other game choices that are really intended not to just "save someone" but in general...save and preserve human life. AND show that you're capable of trust, mercy and having someone else's interests other than your own always in mind. Grey Wardens are supposed to save humanity as a whole, what's the actual harm in saving a few individual humans? I don't agree with her viewpoint that "all these cretins would do it if they could" or falling back on "survival of the fittest" as if it were always a matter of strength. There's power in acts of grace, and being rich enough and strong enough to do more than expected is part of building a reputation and loyalty. The entire point of the game, really.
Being insanely petty enough to resent giving five gold to two recently orphaned kids is ridiculous.