Maybe I'm not getting the big picture here as I['m so used to this being standard practice for airlines (o.k., not that that makes it any more palatable).
I don't really have a problem with the hotel chain requiring the amount of points necessary to acquire a reward at the time of booking.
It seems to me that it would prevent people from holding rooms that may otherwise be difficult to obtain. That is to say, perhaps the person who has enough points decides to try to reserve a room but can not because occupancy is reserved for a reward that may or may not be obtainable by someone who doesn't have enough points accumulated in the long run.
Sure, it stinks for us, but its' a no brainer for the hotel.