"Mission" fixation / Pride (sorry to French colleagues , but I think that may be the main player here ) / Perceived "loss of face" / lack of knowledge of true capabilities of aircraft/ lack of situational awareness / task saturation / failure to prioritise realism over blind faith. . . . . well, maybe not an exhaustive list, but that is what we are up against.
Normally one of the 2 should be sufficiently aware of how screwed up it is, and normally he should be able to communicate this in a timely fashion to his colleague. . . . as I used to mention in a previous company where "normally" was a buzzword. . . . "normally" is merely an expectation - rather than the reality, past present or future.