The wiki description for humiliation states, "Images or animations in which a character is forced by another character to participate in some kind of activity deliberately designed to embarrass, degrade, or otherwise humiliate them." The description for degradation states, "(of or relating to) purposefully damaging one's self respect or reputation." These both sound very similar to me (with the former even lumping in degradation with humiliation), and I don't see a meaningful difference glancing through the tags (though it's a squick for me, so I didn't look closely).
Is there a pressing reason to keep these tags separate?