You're absolutely right to be concerned. However, and if I read your post correctly, is it possible that you may be missing a key point?
IOW, it is doubtful that the drawer "dust dividers" are actually glued throughout the entire length of the rabbet/dado.
It is fairly standard practice in a cabinet with solid wooden sides (as opposed to plywood sides) to only glue the front 3" or so and allow the remainder to float in the rebate in the cabinet sides.
I've done it countless times, and learned to do it from a cabinet maker in England many years ago whose family had been doing it that way for a few hundred.
So far the practice has not let me down either. :)
If I misunderstood your post, holler back.