I look on standings as a matter of trust, rather than a matter of loyalty.
You can be very loyal to people who do not trust you and have little reason to. You can be very disloyal to people who trust you entirely.
The factions seem to use pilot standings as an indication of who can be relied upon and who is owed a good turn or three. It's less "like and dislike," and more history.
Used in that light, they seem pretty valid. Aria, for instance, still has neutral Angel standings (at best), but this works because she's never really proven her personal willingness to do (as missions so often are) "deniable ops" for Curse on a regular basis. Her reliability remains questionable, but that need not have anything to do with how "loyal" she's perceived as being. It's they just don't have much history of direct dealings with her, so her quality and reliability as a mission pilot is unknown and few, if any, favors are owed.
A high-standing character might be viewed by most within the faction as a horrid, mercenary toad who'd sell out his own mother for a few ISK, but also as a useful asset, so important missions and high rewards it is!
That's for capsuleers. A few of the factions could stand to have their standings to each other adjusted.
Cartel and Nation, I'm looking at you.