Full disclosure: someone I am very close to has spent decades as a high-level HR professional in both a large multinational retail corporation (as a regional manager responsible for 6-7 sites in the eastern half of the U.S., ranging from Virginia to Florida to Texas; they spent two thirds of their weeks flying on business trips during those years), and in a major city government (around the level where the mayor recognizes them on sight and remembers their name but doesn't know them personally). They've disclosed more than perhaps they should about how HR operates internally, mostly as venting.
First point: The human response? That's not feasible from a simple workload perspective. Single openings at for minor low-level positions see hundreds of applications; most of the work in the selection process is winnowing that down to a number that's practical to offer interviews to. Candidate selection tends to come down to, as you suggested, discovering which of the more or less equally qualified candidates is the best fit on a personal level -- tl;dr, are they responsible and personable, or do they give off asshole vibes and display worrisome behavioral tendencies?
As an aside, this individual's time in the public sector has been spent largely, apart from day-to-day operations, working to get problem employees within the department into retirement, held accountable for their malfunctions, or into a domain that makes them someone else's problem, and replacing them with people who do their jobs competently and don't spend their work hours with passive-aggressive sniping and petty gossip.
Second point: AA and candidate selection. It's not nearly as black and white (don't hit me!) as it's portrayed. It's not a matter of "this person is X and that person isn't; guess we know who to pick!", and it often comes up (at least in the public sector) in specific fields -- the fire department skewing heavily male is one of the big ones, and it's for basically the same reason as active-duty military. It tends to be less a top-down mandate that "of the next five people you hire, three must be minorities" and more emphasis on shifting recruiting norms to break up good ol' boy networks. When they talk about hiring, "the new employee in X department is [whatever]," it's not the implication of "this is why they were chosen," and more in the same tone of "oh, and they're also ex-military, which is nice because they'll do things without constantly whining about them," except with a different emphasis on a minor up note to an already top-of-the-heap candidate.
But yes. The abuse of temp agencies is a serious problem, and a double-blind method for conducting pre-interview assessment would be wonderful. I'd probably not push farther and go for a text-only interview, though, because behavioral cues often indicate how someone will be like as an employee -- no matter what idiot teenagers think, showing up in street casual and talking to the interviewer like they're your best mate doesn't make a good impression. The point of that whole process from the submission of the resume to the interview is to show that you are capable of being professional and taking things seriously, and that you have a very basic level of competence in self-maintenance and composition.
The overemphasis on social networking (no, not that kind) is also absolutely poisonous. If you know someone, that's a virtual guarantee of getting in. If you can give a dozen prestigious references, that's almost as good. And that's bad.
Welp, race relations is about to become a front-and-center topic again (see: Virginia shooting).
So far it seems more personal than racial, as the shooter was an old employee and sent a manifesto beforehand.
Yeah, while there was something about the shooter claiming discrimination, the details are so vague and we don't even know the details in the first place, so, we don't know if there actually was something racial, or maybe the shooter just percieved it as being racial.
"They didn't dislike you because you were black, they disliked you because you were an asshole."
Basically. Even if this was Alabama the race card wouldn't make me buy a disgruntled ex-employee going postal being anything but a headcase who had easy access to handguns -- thanks, NRA!