Roman theology hews to the Augustine  (tainted by Manchaeism) that all humanity is doomed because everyone was tainted goods since Adam, Eve, despite the slogan, God doesn't make junk. 
And of course Calvin became his best disciple and spread the virus through non Roman Christianity.
Humanity is so dirty that Jesus had to be born of a pure virgin.  And Mary had to be purified by a special cleaning, the immaculate conception; scrubbed clean of original sin so that Jesus would not be infected with our wretched humanity. Hence, the poet's paean to her, "Our tainted nature's solitary boast."  We are all wretched defects. So, as to Catherine's boast, as  rubbish we are combustible to set the world on fire. And aren't we don't a great job?