Everyone is looking for different things and BA may not be for everyone, I am ex military and ex loco captain / training captain and TRE and personally I enjoy BA, I joined 2 years ago at 46 and am a commuter on the minibus fleet, I get one of my top 10 choices every month and get on average 12 days a month at home (in EDI) that said I do bid for llong tours.
I believe that you could pilots in a pub with free beer and free lap dancing (or whatever our female colleagues would prefer!) and as a workforce we would complain as we want lager not bitter and blondes not brunettes...., it's human nature to always think the grass is greener elsewhere.
As an aside I was one of the first to go through CTC, on one occasion the instruction was so bad we (my sim partner and I) stopped the sim ( wrong technique for an EFATO being taught combined with an extremely aggressive attitude for the instructor) he had also spent most of the time slagging off BA and their SOPs so some people may have a bit of a chip on their shoulder.