It was hard to accurately describe the connection between these two people in a sentence. After I rewrote and reread for tons of times, dig deeper and deeper, I came up with this one: Wordsworth and McLuhan both think that seeing is not as important as the ability to feel, as everything coexists at the same time.

William Wordsworth is a British poet born in 1771. He was born to a wealthy family but had deep empathy for the poor as well as nature. He is one of the pioneers in the British Romanticism movement, which deeply emphasizes the two topics above: the poor and nature.
“The eye—it cannot choose but see;
We cannot bid the ear be still;
Our bodies feel, where’er they be,
Against or with our will.
“Expostulation and Reply” Lyrical Ballads

The above stanza quoted in The Medium is the Massage is from Lyrical Ballads. This poem talked about a conversation the poet had with his friend. His friend asks him why he is not reading books to enlighten himself but sitting here on a stone. He replied with the above stanza and said,
“That we can feed this mind of ours
In a wise passiveness.”
“—Then ask not wherefore, here, alone,
Conversing as I may, …”
This poem perfectly shows Wordsworth’s philosophy that “Nature nurtures the mind with a wisdom of its own. A man has only to sit passively in its presence, and it will stimulate his senses in profound ways”. This means Wordsworth gives value on sitting in nature alone, and recognize what nature can give him wisdom too, which might be even more valuable than reading books. Being in nature and open our senses to the surroundings, doesn’t only let us smell, see and hear differently, but also feel differently.
This philosophy is also implied in McLuhan’s book. Here he wrote, “The fact that most conscious experience has little ‘visuality’ in it is lost on him (visual man)”. For a “good” experience and fulfill oneself, one does not necessarily have to rely on visuality.
It might be as well to feel “all factors of the environment and of experience coexist in a state of active interplay”.
In conclusion, I think the reason McLuhan quoted this stanza on page 45 is that it helps him to illustrate this point that we do not live in a primarily visual world. Instead of relying so much on visuality to see and choose the valuable content, we should be able to sense and learn from all the things that coexist around us at the same time.