if it were "the poor"... them is right:
It's what is called "notional agreement in english"
nouns such as "people, etc" ask for a plural form of the verb
however "the plight of the poor"... ( I had the same confusion at the first time , I saw "the poor" not the " the plight of the poor"
you can check on the llink below from AH
time is not on my side