So I gotta ask. What do elves do to survive? They cant survive primarily on stealing.
You are very correct. The unfortunate part of how RPG's are formulated is that things can get too die-hard interpreted, as can be seen in a number of facets here (we all do it in some way on certain topics).
Because of the documentation and how it's worded, I sometimes think we push elves into too 'hard coded' of a theft platform. We think of it too directly, where really it fits better as a subtlety of their culture; they don't respect possession as much, and they, as a result, are more likely to take things they want or to spite someone else, or what-have-you. Same with testing. It isn't that they think 'I'm gonna test this motherfucker and see if he can be trusted.' It's that they just naturally swindle so many people that they are actively anti-being-swindled; trust builds over repeated events.
To directly speak to the question above though, I think that the playerbase pushes the 'I don't like elves' bit too far in one way, and not far enough in another. -Everyone- will be dealing with elves, fairly often; elves are entrepreneurs and active go-getters. They aren't people who steal so that they can do the least work possible, in my eyes. So people that instantly get all 'protect my belt!' are reacting to the state of elves as we've made them by this hyperbolic reading of the documentation, where what it should be is that elves value cunning over prowess, or rather, their prowess is based on cunning. They are interlinked into the community, and being wary of elves is the natural state of knowing that someone is always trying to make every interaction some sort of 'win'; they want to get something, and they're driven in getting it.
So the 'too much in one way' is we immediately treat them all like expert pickpockets, and the 'not enough in the other' is not respecting the mentality itself; they're deeply entrenched in psychology and manipulation and setting themselves up for success in their endeavors. The latter part of this statement makes it so that elves can be wildly successful in a much larger variety of fields without the idea that they're just stealing everything from everyone else all the time to get by. They're doing what jobs they can as mercenaries, tradesmen, hawkers, labor, and what have you, the same as anyone else, but they're constantly trying to stack things into their favor which makes their 'management' hard to maintain. They don't tend to be underlings well, because they will undermine your authority to increase their personal power in that relationship unless they respect said authority.
Or something. Elves are cool. We just one-dimensionalize them a lot.