So, I need to preface this with the fact that I'm not defending any particular method or group. There are poor aviators who make it through in the military (hence why you should really look hard at a guy who has ended his active duty service commitment with less than about 1000 hours or who are light on quals...there's a reason). With that said, I sorta feel like its the other way around. AA has made former military a large slice of their hiring for what seems like generations. It seems that it would be a decision made by the pilots in their hiring departments. Like "most of us are former military and we want more of that even though the HR folks say it's sort of arbitrary". It is brought up often that everybody who applies can fly a plane. It's the other stuff (personality type, background, alcohol tolerance, etc) that really make a candidate a good fit.
What sounds like non-pilots (and even non-HR) reaching into the hiring department is the flows. You have two very different hiring philosophies going on at AA. One is 'let's hire this demographic (#triggered) who is a well known quantity as far as personality and trainability'. The other is 'let's hire this group of dudes who didn't get fired or walk away from the WOs without even finding out who they are. They must be good.' It's the juxtaposition between the two methods that have me scratching my head more than their hard line on either of the two groups.