Would you want the people at the DMV running your intelligence agencies ?
Now, I don’t know about Baker, but even without a drop-down menu, the average American high schooler is thoroughly adept at substituting a valid justification (“grandmother’s funeral,” “one day flu”) for an invalid one (“surfs up!” “first day of fishing season”). I assume the analysts employed by NSA are at least as adept at feeding those in authority the answers they expect. XKeyscore just makes that easier by providing the acceptable justifications in a drop-down menu.