Thousands of hearings of this speech and I don’t think I ever noticed this brief rhyme in the very middle of it. It’s like a little breath, perhaps at the end of a long sentence and in the middle of a long speech.
Also I have questions about these spurns. Is it that Patient Merit is hanging around and The Unworthy One comes along and spurns him? It’s about taking the spurns right?
“Zounds! I should take it!”
Someone making his quietus with a bare bodkin makes total sense, especially after putting up with that long list of whips and scorns.
The Hamlet Project 
I thought I knew precisely what “the spurns…takes” means, but each time I’ve discussed the passage, others have a different, convoluted interpretation:
I constantly feel spurned, rebuffed, proved wrong when I perpetually extend the benefit of the doubt to people who don’t deserve it.
I recognize that as arrogance on my part, but I think it a mistake to believe Hamlet has suddenly assumed a humble posture because he began his list of scorns with “The oppressor’s wrong”. I’ve read that “The proud man’s contumely” was originally “poor man’s contumely”, and “pangs of despised love” originally read “disprized love”.