Because the beeb don't want it here. They won't be able to send the outside broadcast team of millions on yet another overseas jaunt at our expense if it is here.
Because it's a done deal, England won't get it because the whole process is as bent as a butchers hook. Nothing to lose by rubbishing the process, may even do some good.
Also if England do get the tournament then to air the documentary afterwards would probably be construed as being unpatriotic by certain parts of the media.
As Geezer states, the whole process, game & people involved are corrupt to the rafters & it needs to be brought to the surface for the unsuspecting public, & to be made aware that the beautiful game is in fact rather ugly.