>are we discovering a pattern here?

one man's plagiarism is another's literary allusion.

Too true. Joyce questioned whether anything one creates is ever more than just a rehashİ of that which one has learnt up to that point. A major aim of the book was (at least ab extra) to cover all literary styles from all ages in the book. So he used a line or two of W. Whitman to help the reader understand - that's not a crime, it's a homage :-)

Edit in: btw, great wwftd!!