Yes @NCperson I think expecting logic here is difficult! As you pointed out the MD instruction booklet for the resident return states "Any person who can be claimed...". However the nonresident return instruction booklet states "If another taxpayer claims you as a dependent on their tax return, your filing status is dependent taxpayer." This follows the differences between resident and nonresident in the MD code pointed out above.
And adding to this is both resident and nonresident forms have identical filing status sections where box 1 says "If you can be claimed on another person's tax return, use Filing Status 6."
