Or here’s a thought......
Maybe one or both sets of pilots, having reviewed the offer before them, and weighing up the benefits and disadvantages of such a deal, considered that the offer presented to them would open up good opportunities for their future with any perceived disadvantages being insignificant enough to be negligible in the long run. Coming to a different conclusion to others doesn’t make them “spineless”.
What we do know is these aircraft will be placed in the existing operations, and in the case of the A321 the pilots will continue to enjoy the best narrowbody conditions in the country.