Moomba
The reason for this system is the same as it has been for my 35+ years! it allows for more summer vacations. The reason UAL bid in February (not March BTW) for summer was to let the Company firm summer flying up and have more dates available to bid.
The problem isn't the date we bid, it's the fools who have broke a bidding system that worked. And what was that system? At each Domicile's Flight Operations (not CPO because it didn't belong to him or her it was there for the pilots to meet and plan their flights) (domicile because most people at one time lived where they flew out of) the office had a manger who would hand sort the bids after getting the manpower requirements from EXO Planning.
It worked and we knew the person who did the work personally, rather than some Far East programmer over the internet.