tl;dr: Wordsworth humbly urges lawmakers to pass a bill (extending duration of copyright to the greater of 42 years or authors lifetime plus 7 years). No argument or case for or against copyright is articulated
On the contrary, he declines to petition Parliament, saying in essence “I have to believe they’re not idiots enough to listen to that ridiculous printer and publisher lobbying”.
He further adds this reason for not petitioning: that he holds it to be authors’ right, and equitable, that copyright be perpetual—this bill doesn’t go as far as he wants.