.... a demeaning one at that !

Box of Pandora   Fri Oct 20, 2006 10:06 pm GMT
so 'Calling one’s mate stupid, lazy, or selfish implies that his or her entire character can be summed up by a label - a demeaning one at that !"
So what I wish to ask because for me there is both meaning (for me) : whos character can be summed up, (he or her?) and which character can be summed?