I think about it this way~
They're almost like a fraternity (actually they basically are) - they have a set of decent, uncontroversial values and are founded by (probably) decent people, but time passes and they drift further and further from their roots and they even develop sick hazing rituals. There isn't much difference between what probably happened to the Chevaliers and what we know happened to the original Inquisition, the Seekers, the Templars, the Chantry, the Grey Wardens, etc. That doesn't mean that the foundation of the Chevaliers isn't a noble or even moral one (we see Michel de Chevin at least endeavoring to live up to those perceived values in DA:I)
If you've read the ASoIaF series, they're really a mirror of the Kingsguard - there's no reason to say that the Kingsguard is inherently terrible or immoral simply because some of the men who are part of it do terrible/immoral things or the Kingsguard at the current point in time does not adhere to its original tenets.
That aside~ they're a pretty interesting military force and sort of romantic 
I don't think Chevaliers are particularly involved in any way with the greater good - they're knights who are sworn to protect the empire of Orlais.
I'm trying to get into the philosophy of the Chevalier's code itself.
And all philosophy determines what is "the good" to uphold. For example, a hedonist would see "pleasure" or "bliss" as the good to uphold, and anything that takes it away as "not-good" even if it isn't actually "evil" in their eyes.
1. And so, to a person trying to follow the Chevalier's Code in modern Orlas, what is "the good" they are trying to achieve by following the code? Defending the weak? Serving the crown? Defend the country? What is the ideal chevalier doing when following the code?
2. And should a Chevalier be in a position where they have to choose between choosing to defend a village or save the reining monarch, who then, would the Chevalier be more obligated to defend according to their code?
3. And finally, what is the purpose of killing elves in an alienage as part of an initiation ritual in regards to the chevalier code itself?
I'm focusing less on the people and the military order and its members actions, and trying to focus on the code itself, and what the code dictates they actually should do compared to what they actually do.