Long time lurker, first time poster.
Hindsight, you make a compelling case and if I was in my late twenties vs my current late forties I'd probably be nodding my head in agreement.
Mainline carriers have offered professional courtesy in the last couple of years I've been out but since I have no long term aspirations I've declined.
I'm looking to work for a regional - 8 legs a day, on a CRJ taking orders from someone half my age, third of the hours. ... I'm ok with it. A couple of years of flying, for the (121)experience is all I am looking for. I don't see how a few ex military guys who would choose this, do much in the way of harming your future aspirations.