This isn't a new thing, most clubs are doing likewise and did so at the start of the season, United are one of the last clubs left still allowing concession pricing in all games up til now.
They don't need to consult any fans on price rises, yes it's the correct thing do but they don't have too.
It really should be up to the premiership and/or Government to step in to cap any price rises for tickets, but for me the only way it will change is with a salary cap, that way expenditure is kept to a reasonable level and should filter down to the fan going experience.