Well doesn't it kind of make sense
With your first two picks you HAVE to select your keepers. Hence, you would want your keepers listed as your first two options. You will be able to manually select your keepers (if you're there), but no reason not to have that fail safe in place. I know it's tempting to put Tim Duncan as a first priority, but you're not allowed to draft him.
Then, theoretically, if someone misses the draft and doesn't take that keeper, the guy should be there in free agency and the mistake can be corrected if everyone places other teams keepers on their do not draft list.